Re: Regex help needed!
> Oltmans wrote: > >I've a string that looks something like > > > >lksjdfls kdjff lsdfs sdjfls >= "amazon_35343433">sdfsdwelcome > > > > > >>From above string I need the digits within the ID attribute. For > >example, required output from above string is > >- 35343433 > >- 345343 > >- 8898 > > Your string is in /tmp/y in this example: $ grep -o [0-9]+ /tmp/y 345343 35343433 8898 Much simpler, isn't it? But that is not python. Regards Johann -- Johann Spies Telefoon: 021-808 4599 Informasietegnologie, Universiteit van Stellenbosch "And there were in the same country shepherds abiding in the field, keeping watch over their flock by night. And, lo, the angel of the Lord came upon them, and the glory of the Lord shone round about them: and they were sore afraid. And the angel said unto them, Fear not: for behold I bring you good tidings of great joy, which shall be to all people. For unto you is born this day in the city of David a Saviour, which is Christ the Lord."Luke 2:8-11 -- http://mail.python.org/mailman/listinfo/python-list
Re: more efficient?
En Tue, 22 Dec 2009 03:13:38 -0300, Zubin Mithra
escribió:
I have the following two implementation techniques in mind.
def myfunc(mystring):
check = "hello, there " + mystring + "!!!"
print check
OR
structure = ["hello, there",,"!!!"]
def myfunc(mystring):
structure[2] = mystring
output = ''.join(mystring)
i heard that string concatenation is very slow in python; so should i
go for the second approach? could someone tell me why? Would there be
another 'best-practice-style'?
THIS is slow for large enough values of len(items):
def concat(items):
result = ''
for item in items:
result += item
return result
because at each stage it has to create a new string, bigger than the
previous one; it's an n**2 process.
Concatenating just three strings as in your example is fast. The time
spent in dereferencing the "structure" name, indexing into it, creating
the join bound method, iterating, etc. is way longer than the inefficiency
of using + in this case. Anyway, don't blindly trust me, measure it:
python -m timeit -s "def one(x): return 'hello, there '+x+'!!!'"
"one('gabriel')"
10 loops, best of 3: 7.9 usec per loop
python -m timeit -s "lst=['hello, there ','','!!!']" -s "def two(x):
lst[1]=x; return ''.joi
n(lst)" "two('gabriel')"
10 loops, best of 3: 12.4 usec per loop
python -m timeit -s "def three(x): return ''.join(('hello, there
',x,'!!!'))" "three('gabr
iel')"
10 loops, best of 3: 11.9 usec per loop
Anyway, usually, showing a message isn't critical and one doesn't care how
fast it goes, so I'd use this version which is a lot more readable (and
easier to localize, BTW):
def myfunc(mystring):
check = "hello, there {0}!!!".format(mystring)
print check
--
Gabriel Genellina
--
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Re: C Structure rebuild with ctypes
Hi Mark, many thanks for your valuable help. >>> # numVars contains size of returned arrays. Recast to access. >>> varNamesArray = c.cast(varNames,c.POINTER(PCHAR * numVars.value)) >>> varTypesArray = c.cast(varTypes,c.POINTER(INT * numVars.value)) One last question: You created an object varNamesArray as an ctypes array. This object has a method "contents". How do I find out what other methods this objects has? For instance a method to retrieve the size of the array? Is this documented somewhere? Best regards Georg -- http://mail.python.org/mailman/listinfo/python-list
OT Question
Hi; Back when I worked with Zope, they had this nifty form element where I could select from a list of elements on the right and click an arrow to make them go into a list on the left. I need to add this functionality to the store I am creating. What is it called? TIA, beno -- http://mail.python.org/mailman/listinfo/python-list
more efficient?
I have the following two implementation techniques in mind. def myfunc(mystring): check = "hello, there " + mystring + "!!!" print check OR structure = ["hello, there",,"!!!"] def myfunc(mystring): structure[2] = mystring output = ''.join(mystring) i heard that string concatenation is very slow in python; so should i go for the second approach? could someone tell me why? Would there be another 'best-practice-style'? Please help. Thankx in advance! cheers!!! Zubin -- http://mail.python.org/mailman/listinfo/python-list
Re: which pi formula is given in the decimal module documentation?
On Tue, 22 Dec 2009 04:04:56 +, Albert van der Horst wrote: > In article <00b967e1$0$15623$c3e8...@news.astraweb.com>, Steven D'Aprano > wrote: >>Nice work! But I have a question... >> >>On Mon, 21 Dec 2009 20:40:40 +, Albert van der Horst wrote: >> >>> def pi4(): >>> ' Calculate pi by a 5th order process, with favorable stop >>> criterion' >>> precision = 10e-20 >> >> >>Why do you say 10e-20 instead of 1e-19? > > No thought went into that. > Note that the error jumps from 1e-5 to 1e-25 between iterations, so > 1e-20 or 1e-19 hardly makes a difference. Ah, then it's a typo -- you've written TEN e-20 instead of ONE e-20 in your code. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: How to validate the __init__ parameters
On Tue, 22 Dec 2009 00:18:21 +, r0g wrote: > Yikes, glad to be set me straight on that one! Thanks :) It's a pity > though, I really like the way it reads. Is there anything similar with > ISN'T disabled when optimizations are turned on? Yes: an explicit test-and-raise. if not condition: raise Exception > I guess I could do the following but it seems a bit ugly in comparison > :( > > if len(foo) <= 5: raise Exception Write a helper function: def fail_unless(condition, exception=Exception, msg=""): if not condition: raise exception(msg) fail_unless(len(foo) <= 5, ValueError, 'string too long') -- Steven -- http://mail.python.org/mailman/listinfo/python-list
ScrolledText get xy index of rowheader component?
Hi,
I tried to get the xycoordinate of a click of the rowheader column of
Pmw's ScrolledText...and it returns the xycoordinate of the text
portion...even though I supplied it with the rowheader component.
self.scrolledtext.component('rowheader').index("@%d,%d" %
(event.x,event.y))
What am I doing wrong?
the call to my main scrolledtext looks something like this...
self.scrolledtext.index("@%d,%d" % (event.x,event.y))
and works as intended.
Jonathan
--
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Re: which pi formula is given in the decimal module documentation?
En Mon, 21 Dec 2009 17:40:40 -0300, Albert van der Horst escribió: In article , Albert van der Horst wrote: In article , Mark Dickinson wrote: After a cup of coffee, it's much clearer: this just comes from the Taylor series for arcsin(x), applied to x = 1/2 to get asin(1/2) = pi/6. Below you see cos which just calculates cosine with a Taylor series. Then there is pi2() that uses it to calculate pi, for the normal fp precision. pi3() shows the algorithm in its glory and should work for any floating point package. pi4() does the same, if precision is given. And last but not least pi5() that uses the Decimal package to advantage. It precalculates a starting point in 1/5 of the precision. Then it does one more iteration in the full precision. For 1000 digits it is about 5 times faster than pi(), for a moderate increase in complexity. You may try Demo/scripts/pi.py in the source distribution; it uses long integers to compute a continued fraction approximation to pi. I wonder how does it compare to those other algorithms. -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: which pi formula is given in the decimal module documentation?
Nice work! But I have a question... On Mon, 21 Dec 2009 20:40:40 +, Albert van der Horst wrote: > def pi4(): > ' Calculate pi by a 5th order process, with favorable stop > criterion' > precision = 10e-20 Why do you say 10e-20 instead of 1e-19? -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: numpy performance and random numbers
David Cournapeau wrote: On Sun, Dec 20, 2009 at 6:47 PM, Lie Ryan wrote: On 12/20/2009 2:53 PM, sturlamolden wrote: On 20 Des, 01:46, Lie Ryan wrote: Not necessarily, you only need to be certain that the two streams don't overlap in any reasonable amount of time. For that purpose, you can use a PRNG that have extremely high period like Mersenne Twister and puts the generators to very distant states. Except there is no way to find two very distant states and prove they are distant enough. Except only theoretical scientist feel the need to prove it and perhaps perhaps for cryptographic-level security. Random number for games, random number for tmp files, and 99.99% random number users doesn't really need such proves. But the OP case mostly like falls in your estimated 0.01% case. PRNG quality is essential for reliable Monte Carlo procedures. I don't think long period is enough to guarantee those good properties for // random generators - at least it is not obvious to me. David My simulation program is Monte Carlo, but the complexity and variety of all the interactions ensure that PRNG sequence overlap will have no discernible effect. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python-list Digest, Vol 75, Issue 226
En Mon, 21 Dec 2009 16:30:13 -0300, Pulkit Agrawal escribió: I am writing a script wherein I need to merge files into existing tar.gz files. Currently, I am using tarfile module. I extract the tar.gz to a tempdir and copy the new file there and re-compress all the files back into a tar.gz. Is there a better way to do it? Since noone answered yet: no, I don't think you can avoid to decompress and recompress those files. -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.1.1 installer botches upgrade when installation is not on C drive.
En Mon, 21 Dec 2009 15:25:05 -0300, John Nagle escribió: I just installed "python3.1.1.msi" on a system that had "python3.1.msi" installed in "D:/python31". The installer found the old installation in "D:/python31", partially trashed it, and then installed the new version in "C:/python31". I uninstalled the failed install, and reinstalled. On a new install, the installer prompts for the destination dir, and that works. Upgrade installs, though, are botched. That's strange. I usually install into d:\apps\pythonNN. Apart from the fact that the installer always suggests c:\pythonNN (even if already installed in another location) I don't remember a problem like yours. Which Windows version? -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: How to validate the __init__ parameters
r0g wrote: > Steven D'Aprano wrote: >> On Mon, 21 Dec 2009 21:49:11 +, r0g wrote: >> >>> I use assertions myself e.g. >>> >> foo = "123456" >> assert len(foo) <= 5 >>> Traceback (most recent call last): >>> File "", line 1, in >>> AssertionError >>> >>> >>> Dunno if this would be considered good or bad programming practice by >>> those more experienced than I (comment always welcome!) but it works for >>> me :) >> >> Bad practice. >> >> Assertions are ignored when you run Python with the -O (optimization) >> command line switch. Your code will behave differently if you use >> assertions. So you should never use assertions for error-checking, except >> perhaps for quick-and-dirty throw-away scripts. >> >> Assertions are useful for testing invariants and "this will never happen" >> conditions. A trivial example: >> >> result = math.sin(2*math.pi*x) >> assert -1 <= result <= 1 >> >> Assertions are also useful in testing, although be careful: since the >> assert statement is ignored when running with -O, that means you can't >> test your application when running with -O either! But do not use them >> for data validation unless you're happy to run your application with no >> validation at all. >> >> >> > > > Yikes, glad to be set me straight on that one! Thanks :) It's a pity > though, I really like the way it reads. Is there anything similar with > ISN'T disabled when optimizations are turned on? > > I guess I could do the following but it seems a bit ugly in comparison :( > > if len(foo) <= 5: raise Exception > OK,so here's a revolutionary thought. Since you have now discovered that a) you can't reliably rely on an AssertionError being raised by an assert that asserts an invariant; b) the alternative of explicitly raising an exception is at least somewhat uglier; and c) you have to do *something*. Er, actually, do you? What's the exact reason for requiring that a creator argument be of a specific type? So operations on the instances don't go wrong? Well, why not just admit that we don't have control over everything, and just *let things go wrong* when the wrong type is passed? What will then happen? Why, an exception will be raised! You might argue that the user, seeing the traceback from the exception, won't know what to make of it. In response to which I would assert (pun intended) that neither would the traceback produced by the assertion failure. Given that somebody who knows what they are talking about has to cast their eye over a traceback to understand what's wrong with the program, it's not much extra effort for that person realise that a method has been called with an invalid argument type. I accept that there are legitimate arguments in opposition to this point of view, but it has a certain engineering efficiency (as long as we are prepared to work inside frameworks like Django that will encapsulate any error tracebacks so that you see all the information that you need, and the user gets some other inexplicable error message like "A programmer probably screwed up). In other words, "be prepared to fix your program when it goes wrong" is a valid alternative to trying to anticipate every single last thing that might go wrong. This philosophy might not be appropriate for extra-terrestrial exploration, but most Python programmers aren't doing that. regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 PyCon is coming! Atlanta, Feb 2010 http://us.pycon.org/ Holden Web LLC http://www.holdenweb.com/ UPCOMING EVENTS:http://holdenweb.eventbrite.com/ -- http://mail.python.org/mailman/listinfo/python-list
python - fetching, post, cookie question
hi...
the following sample is an attempt to fetch two subsequent pages from a
sameple site. (it's public) the script attempts to implement a request,
using the POST method, as well as as cookies. Testing using
LiveHttpHeaders/Firefox indicates that the app uses post/cookies, and it
doesn't work if cookies are disabled on the browser.
the query for the post, was obtained via the LiveHttpHeaders app.
I can get the 1st page, but not the 2nd. I'm assuming that I'm somehow
screwing up the use/implementation of the cookies.. Searching the net isn't
shedding any light for now..
After showing the 1sr page, the 2nd page is viewed from the browser, by
selecting a 'next' link, which invokes a jscript submit for the DOM. The
post data is captured via LiveHttpHeaders.. It's this data that forms the
data for the 2nd Post attempt in the test..
Any thoughts/comments/pointers would be helpful... (and yeah the test is
ugly..!)
thanks
-tom
#!/usr/bin/python
#test python script
import re
import urllib
import urllib2
import sys, string, os
from mechanize
import Browser
import mechanize
import cookielib
#
# Parsing App Information
# datafile
cj = "p"
COOKIEFILE = 'cookies.lwp'
#cookielib = 1
urlopen = urllib2.urlopen
#cj = urllib2.cookielib.LWPCookieJar()
cj = cookielib.LWPCookieJar()
#cj = ClientCookie.LWPCookieJar()
Request = urllib2.Request
br = Browser()
if cj != None:
print "sss"
#install the CookieJar for the default CookieProcessor
if os.path.isfile(COOKIEFILE):
cj.load(COOKIEFILE)
print "foo\n"
if cookielib:
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
urllib2.install_opener(opener)
print "foo2\n"
user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
values1 = {'name' : 'Michael Foord',
'location' : 'Northampton',
'language' : 'Python' }
headers = { 'User-Agent' : user_agent }
if __name__ == "__main__":
# main app
baseurl="https://pisa.ucsc.edu/class_search/index.php";
print "b = ",baseurl
print "b = ",headers
query="action=results&binds%5B%3Aterm%5D=2100&binds%5B%3Areg_status%5D=O&bin
ds%5B%3Asubject%5D=&binds%5B%3Acatalog_nbr_op%5D=%3D&binds%5B%3Acatalog_nbr%
5D=&binds%5B%3Atitle%5D=&binds%5B%3Ainstr_name_op%5D=%3D&binds%5B%3Ainstruct
or%5D=&binds%5B%3Age%5D=&binds%5B%3Acrse_units_op%5D=%3D&binds%5B%3Acrse_uni
ts_from%5D=&binds%5B%3Acrse_units_to%5D=&binds%5B%3Acrse_units_exact%5D=&bin
ds%5B%3Adays%5D=&binds%5B%3Atimes%5D=&binds%5B%3Aacad_career%5D="
request = urllib2.Request(baseurl, query, headers)
response = urllib2.urlopen(request)
print " \n"
#print req
print "\n 55\n"
print "res = ",response
x1 = response.read()
#x1 = res.read()
print x1
#sys.exit()
cj.save(COOKIEFILE)
# resave cookies
if cj is None:
print "We don't have a cookie library available - sorry."
print "I can't show you any cookies."
else:
print 'These are the cookies we have received so far :'
for index, cookie in enumerate (cj):
print index, ' : ', cookie
cj.save(COOKIEFILE)
print "ffgg \n"
for index, cookie in enumerate (cj):
print index, ' : ', cookie
#baseurl ="http://students.yale.edu/oci/resultList.jsp";
baseurl="https://pisa.ucsc.edu/class_search/index.php";
query="action=next&Rec_Dur=100&sel_col%5Bclass_nbr%5D=1&sel_col%5Bclass_id%5
D=1&sel_col%5Bclass_title%5D=1&sel_col%5Btype%5D=1&sel_col%5Bdays%5D=1&sel_c
ol%5Btimes%5D=1&sel_col%5Binstr_name%5D=1&sel_col%5Bstatus%5D=1&sel_col%5Ben
rl_cap%5D=1&sel_col%5Benrl_tot%5D=1&sel_col%5Bseats_avail%5D=1&sel_col%5Bloc
ation%5D=1"
request = urllib2.Request(baseurl, query, headers)
response = urllib2.urlopen(request)
print " \n"
#print req
print "\n 55\n"
print "res = ",response
x1 = response.read()
#x1 = res.read()
print x1
sys.exit()
req = Request(baseurl, query, headers)
print " \n"
#print req
print "\n 55\n"
#br.open(req)
res = urlopen(req)
print " \n"
x1 = res.read()
print x1
sys.exit()
--
http://mail.python.org/mailman/listinfo/python-list
[no subject]
hi...
the following sample is an attempt to fetch two subsequent pages from a
sameple site. (it's public) the script attempts to implement a request,
using the POST method, as well as as cookies. Testing using
LiveHttpHeaders/Firefox indicates that the app uses post/cookies, and it
doesn't work if cookies are disabled on the browser.
the query for the post, was obtained via the LiveHttpHeaders app.
I can get the 1st page, but not the 2nd. I'm assuming that I'm somehow
screwing up the use/implementation of the cookies.. Searching the net isn't
shedding any light for now..
After showing the 1sr page, the 2nd page is viewed from the browser, by
selecting a 'next' link, which invokes a jscript submit for the DOM. The
post data is captured via LiveHttpHeaders.. It's this data that forms the
data for the 2nd Post attempt in the test..
Any thoughts/comments/pointers would be helpful... (and yeah the test is
ugly..!)
thanks
-tom
#!/usr/bin/python
#test python script
import re
import urllib
import urllib2
import sys, string, os
from mechanize
import Browser
import mechanize
import cookielib
#
# Parsing App Information
# datafile
cj = "p"
COOKIEFILE = 'cookies.lwp'
#cookielib = 1
urlopen = urllib2.urlopen
#cj = urllib2.cookielib.LWPCookieJar()
cj = cookielib.LWPCookieJar()
#cj = ClientCookie.LWPCookieJar()
Request = urllib2.Request
br = Browser()
if cj != None:
print "sss"
#install the CookieJar for the default CookieProcessor
if os.path.isfile(COOKIEFILE):
cj.load(COOKIEFILE)
print "foo\n"
if cookielib:
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
urllib2.install_opener(opener)
print "foo2\n"
user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
values1 = {'name' : 'Michael Foord',
'location' : 'Northampton',
'language' : 'Python' }
headers = { 'User-Agent' : user_agent }
if __name__ == "__main__":
# main app
baseurl="https://pisa.ucsc.edu/class_search/index.php";
print "b = ",baseurl
print "b = ",headers
query="action=results&binds%5B%3Aterm%5D=2100&binds%5B%3Areg_status%5D=O&bin
ds%5B%3Asubject%5D=&binds%5B%3Acatalog_nbr_op%5D=%3D&binds%5B%3Acatalog_nbr%
5D=&binds%5B%3Atitle%5D=&binds%5B%3Ainstr_name_op%5D=%3D&binds%5B%3Ainstruct
or%5D=&binds%5B%3Age%5D=&binds%5B%3Acrse_units_op%5D=%3D&binds%5B%3Acrse_uni
ts_from%5D=&binds%5B%3Acrse_units_to%5D=&binds%5B%3Acrse_units_exact%5D=&bin
ds%5B%3Adays%5D=&binds%5B%3Atimes%5D=&binds%5B%3Aacad_career%5D="
request = urllib2.Request(baseurl, query, headers)
response = urllib2.urlopen(request)
print " \n"
#print req
print "\n 55\n"
print "res = ",response
x1 = response.read()
#x1 = res.read()
print x1
#sys.exit()
cj.save(COOKIEFILE)
# resave cookies
if cj is None:
print "We don't have a cookie library available - sorry."
print "I can't show you any cookies."
else:
print 'These are the cookies we have received so far :'
for index, cookie in enumerate (cj):
print index, ' : ', cookie
cj.save(COOKIEFILE)
print "ffgg \n"
for index, cookie in enumerate (cj):
print index, ' : ', cookie
#baseurl ="http://students.yale.edu/oci/resultList.jsp";
baseurl="https://pisa.ucsc.edu/class_search/index.php";
query="action=next&Rec_Dur=100&sel_col%5Bclass_nbr%5D=1&sel_col%5Bclass_id%5
D=1&sel_col%5Bclass_title%5D=1&sel_col%5Btype%5D=1&sel_col%5Bdays%5D=1&sel_c
ol%5Btimes%5D=1&sel_col%5Binstr_name%5D=1&sel_col%5Bstatus%5D=1&sel_col%5Ben
rl_cap%5D=1&sel_col%5Benrl_tot%5D=1&sel_col%5Bseats_avail%5D=1&sel_col%5Bloc
ation%5D=1"
request = urllib2.Request(baseurl, query, headers)
response = urllib2.urlopen(request)
print " \n"
#print req
print "\n 55\n"
print "res = ",response
x1 = response.read()
#x1 = res.read()
print x1
sys.exit()
req = Request(baseurl, query, headers)
print " \n"
#print req
print "\n 55\n"
#br.open(req)
res = urlopen(req)
print " \n"
x1 = res.read()
print x1
sys.exit()
--
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Re: C Structure rebuild with ctypes
"Georg" wrote in message
news:7padi2fsm...@mid.individual.net...
Hi Mark,
many thanks for your help. I tried your code in my program and it worked.
I would like to understand what the code is doing and I have some
questions to it.
Are you passing in these values, or are they being returned? To me the
depth of the pointer references implies numVars, varNames, and varTypes
are out parameters. I'll assume that for now. If they are in/out
parameters let me know.
Your exactly right: the parameters numVars, varNames and VarTypes are out
paramters.
I mocked up a DLL to test returning values of these types. I used VS2008
and compiled with "cl /LD func.c":
--- func.c ---
#include
#define FUNCDLL
#include "func.h"
static char* g_data[] = {"one","two","three"};
static int g_types[] = {1,2,3};
FUNCAPI int func (int handle, int *numVars, char ***varNames, int
**varTypes)
{
*numVars = _countof(g_data);
*varNames = g_data;
*varTypes = g_types;
return handle + 1;
}
What does the signature FUNCAPI do in this context?
In Microsoft's compiler, to export functions from a DLL, one way is to mark
functions with __declspec(dllexport). To import functions from a DLL, the
functions should be marked with __declspec(dllimport). FUNCAPI is declared
in func.h below to be one of these definitions. In the actual DLL source,
FUNCDLL is defined before including the header to declare all the
FUNCAPI-tagged functions in the header as exported.
In an executable file that uses the DLL, it can include func.h without
defining FUNCDLL, and all the FUNCAPI-tagged functions in the header will be
declared imported.
It was overkill for this example, but I had code skeletons for DLLs already.
The example could be simplified by replacing FUNCAPI in func.cpp with
__declspec(dllimport) and not using func.h at all.
--- func.h ---
#ifdef FUNCDLL
#define FUNCAPI __declspec(dllexport)
#else
#define FUNCAPI __declspec(dllimport)
#endif
FUNCAPI int func (int handle, int *numVars, char ***varNames, int
**varTypes);
Do I need to wrap the compiled DLL file this way? I can load the DLL with
the CDLL method, make calls to simple functions, e.g. no parameters,
returning stirng and get the right values.
No, if the DLL is exporting functions correctly this method doesn't have to
be used. As I said above it was a code template I already had. IIRC, the
Microsoft code wizard to generate a DLL uses this method. I didn't have
your DLL to test with, so I had to make my own and I wanted you to see the
assumptions I made about its implementation, in case they were wrong :^)
I added all the code from your func.py module to the code I already had.
And -- it works fine and delivers the expected results.
--- func.py ---
... cut ...
# int func (int handle, int *numVars, char ***varNames, int **varTypes)
func = c.CDLL('func').func
func.restype = INT
func.argtypes = [INT,PINT,PPPCHAR,PPINT]
I added this part to my program.
# allocate storage for the out parameters
numVars = INT()
varNames = PPCHAR()
varTypes = PINT()
I added this part also.
print func(5,c.byref(numVars),c.byref(varNames),c.byref(varTypes))
I called the library routine.
# numVars contains size of returned arrays. Recast to access.
varNamesArray = c.cast(varNames,c.POINTER(PCHAR * numVars.value))
varTypesArray = c.cast(varTypes,c.POINTER(INT * numVars.value))
What does this cast? How do I know how I have to cast the objects returned
from the library function?
The library is returning a pointer to an array of some size you didn't know
in advance. So, for example, we passed varTypes as the address of a pointer
to int, and a pointer to int was returned. Since varTypes was declared as a
pointer to a single int, I recast it to a pointer to "numVars" ints. This
allowed me to use indexing syntax ([n]) to access the other elements of the
returned array.
What kind of objects do I get? I learned that the values of objects
created by the ctypes module are accessed using object.value?
numVars is the name of an INT() object, not a Python int. numVars.value
returns the Python int that the INT represents. An example might be
helpful:
>>> import ctypes
>>> x=ctypes.c_int(5)
>>> x # here x is a ctypes object.
c_long(5)
>>> x.value # here is the Python value it represents
5
>>> y=(ctypes.c_int * x)() # I want to create an array of c_ints
Traceback (most recent call last):
File "", line 1, in
TypeError: can't multiply sequence by non-int of type 'c_long'
>>> y=(ctypes.c_int * x.value)() # It works with Python values.
>>> y
<__main__.c_long_Array_5 object at 0x00A04D50>
>>> y[0]
0
>>> y[1]
0
Hope that helps,
Mark
--
http://mail.python.org/mailman/listinfo/python-list
Re: Windows, IDLE, __doc_, other
Stephen Hansen wrote: On Mon, Dec 21, 2009 at 2:57 PM, W. eWatson wrote: This has got to be some sort of IDLE issue then. Huh? How do you figure? When I run a simple program. If I open this program in the IDLE editor: #import math print "hello, math world." print cos(0.5) print sin(0.8) then I get print cos(0.5) NameError: name 'cos' is not defined Of course, because -- cos is not defined. As I stated in my previous email, "math" has to be imported to be used. Yes, I agree. OK, >>> dir() ['__builtins__', '__doc__', '__file__', '__name__', 'idlelib'] Fine. I now change the code to include import mat get the same: print cos(0.5) NameError: name 'cos' is not defined Yes, because cos is inside math. True enough. Hang in there. [snip Now, I go to the script and enter from math import * dir is now bulked up with the math functions. I change back math.cos to cos and the program runs well. This sort of figures. Apparently, I've added to the namespace by importing with *. Apparently? -- you precisely and explicitly added every object in 'math' to your current namespace. "from math import *" does precisely that. Well, it's a big surprise to me, because I thought each time I ran from the editor that it reloaded the modules in my imports, and cleared out any it didn't find. My point is that I'm betting different results. OK, fine. It appears the same thing happens with I modify the program itself with from math import * Different results? What different results are you talking about? It seems to me as I fool around with interpreter under the script window, I"m creating a mess out of the namespace the program uses, and the program responds incorrectly. If you want to access 'sin' without 'math.', you'll have to do 'from math import *' in each file where you want to do that. So IDLE is not clearing the namespace each time I *run* the program. This is not good. I've been fooled. So how do I either clear the namespace before each Run? Do I have to open the file in the editor again each time before trying to Run it? I hope there's a better way. How do you figure its 'not clearing the namespace'? In which namespace? I fire up IDLE, and start a new file, and put in a single Try this sequence. I just started plugging away again with IDLE and am pretty convinced that IDLE is something of an enemy. I started afresh loading this into the editor: import math print "hello, math world." print math.cos(0.5) print math.sin(0.8) Run works fine. No errors. Now I do: >>> dir() ['__builtins__', '__doc__', '__file__', '__name__', 'idlelib', 'math'] >>> OK, swell. Now I import via the script window >>> import numpy as np >>> dir() ['__builtins__', '__doc__', '__file__', '__name__', 'idlelib', 'math', 'np'] I think I'm adding to the namespace, both the program the shell sees, because adding this ref to np in the program works fine. import math print "hello, math world." print math.cos(0.5) print math.sin(0.8) print np.sin(2.2) --- There's no np in that code, but yet it works. It must be in the namespace it sees, and it was put there through the interactive shell. line: "a = 1". I choose Run Module, and it runs it. I verify in the interactive interpreter that a is 1. I then change that file to "a = a + 1", and run it. Now, it errors out-- of course-- because IDLE "cleared" the namespace and re-ran the module. Hmmm, that appears to contrary to my numpy experience. I've never seen any re-starting msg. Python 2.5.2 (r252:60911, Feb 21 2008, 13:11:45) [MSC v.1310 32 bit (Intel)] on win32 Type "copyright", "credits" or "license()" for more information. It says in the interpreter its restarting, even. --S -- http://mail.python.org/mailman/listinfo/python-list
how to register with pypi - no such setup.py
And the next question in the series - how to make sure the resulting package has a setup.py file? The basic steps are... - build a python package - create a minimal setup.py - (github it, natch) - throw it at pypi with: python setup.py bdist upload - attempt to install it with: sudo pip install my_package and get this: Downloading/unpacking my_package ... IOError: [Errno 2] No such file or directory: '.../setup.py' So the irony is if I had to use setup.py to build the MyPackage..tar.gz, why isn't it inside it? Any tips? (the actual package name is censored because I don't need people finding this if they google for that!;) -- http://mail.python.org/mailman/listinfo/python-list
PyTrie 0.1
I'm pleased to announce the first release of PyTrie, a pure Python implementation of the trie (prefix tree) data structure [1]. Tries extend the mapping interface with methods that facilitate finding the keys/values/items for a given prefix, and vice versa, finding the prefixes (or just the longest one) of a given key K. Project links: - PyPI entry: http://pypi.python.org/pypi/PyTrie - Documentation: http://packages.python.org/PyTrie - Repository: http://bitbucket.org/gsakkis/pytrie Regards, George [1] http://en.wikipedia.org/wiki/Trie -- http://mail.python.org/mailman/listinfo/python-list
Re: Please Help Publicize PyCon
*Bitten once again by 'reply all', my apologies john.* Brilliant troll :D Well done! I, for one, am looking forward to watching the videos of the talks, since I can not attend myself (hi college education!). On Mon, Dec 21, 2009 at 9:31 AM, John Nagle wrote: > Steve Holden, Chairman, PSF wrote: > >> Hi,everyone. >> >> This year I hope all readers of this list will assist me in crass >> commercial promotion of next year's PyCon. >> > ... > > One particularly effective way for you prodigious email producers to >> assist is to something to your signature (as you will see I have done). >> > ... > > This guy wants people to spam for him to promote his $300 conference. > > Don't support spammers. Boycott PyCon. > >John Nagle > > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
Re: how to register with pypi
If you have never used PGP before, you *really* shouldn't register a PGP key ID in PyPI. I suppose your key doesn't have any counter signatures, anyway. Nope, thanks, I'm already in. The pypi page could mark the field "optional". I just associated it, conceptually, with the Github SSH key, and with passwordless login in general, and assumed it was required... -- http://mail.python.org/mailman/listinfo/python-list
Re: How to validate the __init__ parameters
Steven D'Aprano wrote: > On Mon, 21 Dec 2009 21:49:11 +, r0g wrote: > >> I use assertions myself e.g. >> > foo = "123456" > assert len(foo) <= 5 >> Traceback (most recent call last): >> File "", line 1, in >> AssertionError >> >> >> Dunno if this would be considered good or bad programming practice by >> those more experienced than I (comment always welcome!) but it works for >> me :) > > > Bad practice. > > Assertions are ignored when you run Python with the -O (optimization) > command line switch. Your code will behave differently if you use > assertions. So you should never use assertions for error-checking, except > perhaps for quick-and-dirty throw-away scripts. > > Assertions are useful for testing invariants and "this will never happen" > conditions. A trivial example: > > result = math.sin(2*math.pi*x) > assert -1 <= result <= 1 > > Assertions are also useful in testing, although be careful: since the > assert statement is ignored when running with -O, that means you can't > test your application when running with -O either! But do not use them > for data validation unless you're happy to run your application with no > validation at all. > > > Yikes, glad to be set me straight on that one! Thanks :) It's a pity though, I really like the way it reads. Is there anything similar with ISN'T disabled when optimizations are turned on? I guess I could do the following but it seems a bit ugly in comparison :( if len(foo) <= 5: raise Exception Roger. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to register with pypi
>> The key ID should be an eight-digit string, such as EA5BBD71 (i.e. a >> 32-bit key ID). > > pretend I was someone who had never ever used PGP before. > > pgp -kg, then what? I don't have pgp, only gpg. In gpg --list-keys, it's the 32-bit ID that gets listed. Try -kv. If you have never used PGP before, you *really* shouldn't register a PGP key ID in PyPI. I suppose your key doesn't have any counter signatures, anyway. Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: Beginner question: binary data and socket.send
On Mon, Dec 21, 2009 at 3:31 PM, Boris Epel wrote: > Hi! Please help with the problem: > send over TCPIP data packet organized as 6 bytes of identifier, > integer (LSB) and length of following binary data, binary data > the clear part: create socket, connect it, use send, close socket > the unclear part: create string with required data to use with send > what I tried: You probably want to take a look at the "struct" module to pack your byte-strings with binary data. HTH, --S -- http://mail.python.org/mailman/listinfo/python-list
Re: Threading with queues
Stephen Hansen wrote: On Mon, Dec 21, 2009 at 3:12 PM, Gib Bogle wrote: #spawn a pool of threads, and pass them queue instance for i in range(5): t = ThreadUrl(queue,i) t.setDaemon(True) t.start() #populate queue with data for host in hosts: queue.put(host) This is indented over one indentation level too much. You want it to be at the same level as the for above. Here, its at the same level with "t" -- meaning this entire loop gets repeated five times. I sorta really recommend a tab width of 4 spaces, not 2 :) At 2, its _really_ hard (especially if you're newer to Python) to see these kinds of issues and since indentation is program logic and structure in Python, that's bad... especially since your comment is indented to the right level, but the code isn't :) --S It turns out that this code isn't a great demo of the advantages of threading, on my system anyway. The time taken to execute doesn't vary much when the number of threads is set anywhere from 1 to 6. -- http://mail.python.org/mailman/listinfo/python-list
Re: numpy performance and random numbers
On 2009-12-21 16:57 PM, r0g wrote: sturlamolden wrote: On 19 Des, 16:20, Carl Johan Rehn wrote: How about mulit-core or (perhaps more exciting) GPU and CUDA? I must admit that I am extremely interested in trying the CUDA-alternative. Obviously, cuBLAS is not an option here, so what is the safest route for a novice parallel-programmer? The problem with PRNG is that they are iterative in nature, and maintain global states. They are therefore very hard to vectorize. A GPU will not help. The GPU has hundreds of computational cores that can run kernels, but you only get to utilize one. Parallel PRNGs are an unsolved problem in computer science. Surely you could have as many totally independent cores as you like independently spitting out random bits whenever they feel like it to make an equally random bitstream? would have thought the only issue would be ensuring high quality bitstream was used to seed each thread no? No. For most quality PRNGs, all seeds are equal (with a few minor exceptions. E.g. for the Mersenne Twister, a state vector of all zeros will yield only zeros, but any nontrivial state vector puts the PRNG into the same orbit, just at different places). There is no notion of a "high quality seed". The problem is that during the run, the separate PRNGs may overlap, which will reduce the independence of the samples. That said, the enormous length of the Mersenne Twister's period helps a lot. You can use an ungodly number of streams and run length without having a physically realizable chance of overlap. The chance of having a bug in your simulation code is overwhelmingly greater. There are also algorithms that can initialize a given number of PRNGs with different parameters (*not* seeds) that are guaranteed not to overlap. No one has implemented this for numpy, yet. -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: Object Relational Mappers are evil (a meditation)
On Mon, 21 Dec 2009 11:44:29 -0500, J Kenneth King wrote: > A programmer that > lacks critical thinking is a bad programmer. The language they use has > no bearing on such human facilities. That's nonsense, and I can demonstrate it by reference to a single programming language, namely Python. For many years, Python had no ternary if operator: result = x if condition else y Instead the accepted, idiomatic Python way of writing this was to use short-circuit booleans: result = condition and x or y However this idiom is buggy! If x is a false-value (say, 0) then result gets set to y no matter what the value of condition. This buggy idiom survived many years of Python development, missed by virtually everyone. Even coders of the calibre of Raymond Hettinger (who neither lacks critical thinking nor is a bad programmer) have been bitten by this: "The construct can be error-prone. When an error occurs it can be invisible to the person who wrote it. I got bitten in published code that had survived testing and code review: ..." http://mail.python.org/pipermail/python-dev/2005-September/056510.html This is a clear and obvious case where a language feature (in this case, the lack of a feature) encouraged an otherwise excellent coder to make an error. It was a very subtle error, which was not picked up by the author, the tests, or the coder reviewer(s). Had Python been different (either by including a ternary if statement, or by forcing and/or to return bools only) then this bug never would have occurred. Of course awful programmers will be awful programmers in any language, and excellent programmers will be excellent programmers in many languages. (I say "many" rather than any deliberately. There's a reason why nobody uses languages like Brainf*ck, Whitespace, Ook or Intercal for real work.) But most coders are neither awful nor excellent. The language DOES make a difference: the quality of a technician depends partly on the quality of his tools, and programmers are no different. If you don't believe me, imagine writing code in a language without functions or loops, so you have to use GOTO for everything. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: How to validate the __init__ parameters
On Mon, 21 Dec 2009 21:49:11 +, r0g wrote: > I use assertions myself e.g. > foo = "123456" assert len(foo) <= 5 > Traceback (most recent call last): > File "", line 1, in > AssertionError > > > Dunno if this would be considered good or bad programming practice by > those more experienced than I (comment always welcome!) but it works for > me :) Bad practice. Assertions are ignored when you run Python with the -O (optimization) command line switch. Your code will behave differently if you use assertions. So you should never use assertions for error-checking, except perhaps for quick-and-dirty throw-away scripts. Assertions are useful for testing invariants and "this will never happen" conditions. A trivial example: result = math.sin(2*math.pi*x) assert -1 <= result <= 1 Assertions are also useful in testing, although be careful: since the assert statement is ignored when running with -O, that means you can't test your application when running with -O either! But do not use them for data validation unless you're happy to run your application with no validation at all. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Threading with queues
Stephen Hansen wrote: On Mon, Dec 21, 2009 at 3:12 PM, Gib Bogle wrote: #spawn a pool of threads, and pass them queue instance for i in range(5): t = ThreadUrl(queue,i) t.setDaemon(True) t.start() #populate queue with data for host in hosts: queue.put(host) This is indented over one indentation level too much. You want it to be at the same level as the for above. Here, its at the same level with "t" -- meaning this entire loop gets repeated five times. I sorta really recommend a tab width of 4 spaces, not 2 :) At 2, its _really_ hard (especially if you're newer to Python) to see these kinds of issues and since indentation is program logic and structure in Python, that's bad... especially since your comment is indented to the right level, but the code isn't :) --S Aarrh! Caught by the obvious Python trap that everyone knows about! In my defense, it's wrong on the web site. I agree, 4 spaces is the best plan. Thanks very much! -- http://mail.python.org/mailman/listinfo/python-list
Re: Object Relational Mappers are evil (a meditation)
J Kenneth King wrote: > c) This has nothing to do with programming languages. A programmer that > lacks critical thinking is a bad programmer. The language they use has > no bearing on such human facilities. The language may well have a bearing on the quality of the programs generated though, which is what most people care about. A dolt writing in python is far less likely to write a program that bluescreens the users machine than a comparative dolt writing the same program in C or assembler. Of course two gurus writing in different languages would produce equally good results but gurus are considered gurus by virtue of their scarcity. Back in the real world the further into dolthood you venture, the more the more important the design of the language becomes to the quality of outputs you can expect to get from your code monkeys. Take 100 perfectly average programmers and give them the same programs to write in a variety of languages, you will get higher quality results from some languages than others i.e. not all languages are equal. I think it's fair to say the ones that give the best results encourage good coding and the ones that give the worst results encourage bad coding. If you don't believe it's possible to have a language that encourages bad coding practices consider this one I just made up, I call it Diethon.. It's entirely the same as Python 2.6 except that any syntax errors that happen within class definitions cause the interpreter to send offensive emails to everyone in your contacts list and then delete your master boot record. Unsurprisingly users of this language are reluctant to try to create object oriented code and resort to ugly struct and list based paradigms instead. Roger. -- http://mail.python.org/mailman/listinfo/python-list
Beginner question: binary data and socket.send
Hi! Please help with the problem: send over TCPIP data packet organized as 6 bytes of identifier, integer (LSB) and length of following binary data, binary data the clear part: create socket, connect it, use send, close socket the unclear part: create string with required data to use with send what I tried: buffer = [for i in range(23)]; buffer[0:5]="BB" command = 0 buffer[6:9] = (command >> i & 255 for i in range(0,32,8)) datalength = 10 buffer[10:13] = (datalength >> i & 255 for i in range(0,32,8)) here i surrendered since buffer is a list of int and i need string ... Suggestions are appreciated! boris -- http://mail.python.org/mailman/listinfo/python-list
Re: Using Python to Execute a C or FORTRAN Program (Windows)
W. eWatson wrote: Mensanator wrote: On Dec 14, 8:14�pm, "W. eWatson" wrote: I think Python is capable of executing a compiled C or FORTRAN program, Sure, if it was compiled to an .exe file. and maybe even getting some parameters passed back. Sure, if the program prints to stdout. Does anyone have a example of how this might be done? I'm running under Win XP Pro. Here's one. The test program is factor.exe (included in the MIRACL library). I recompiled it (factor!.exe) to produce consitent output. ... Thanks. OK, I think I can follow that. I want to pass it along to someone who either missed this possibility in some coding, ignored it, or felt more comfortable about just writing the whole program from scratch in c++. His program was originally written in Python, but a new hardware device (capture card) had no good interface with Python, so he wrote it in C++, which does. From my knowledge of the Python program before the entry of c++, it seems he could have farmed out the hardware interface in much the same way he had done it before with a capture card well know to him. Would the same Python interface work for a compiled C++ program? I am working on a Python UI (PyQt4) to a Fortran program. The approach I've taken is to build the Fortran code as a DLL (or .so). Python can load the library and call a procedure that initiates execution. I'm using sockets to pass data of different types back to the Python program. This is a work in progress, and I'm learning Python as we go. -- http://mail.python.org/mailman/listinfo/python-list
Re: numpy performance and random numbers
sturlamolden wrote: On 19 Des, 22:58, sturlamolden wrote: If you pick two random states (using any PRNG), you need error- checking that states are always unique, i.e. that each PRNG never reaches the starting state of the other(s). Another note on this: Ideally, we would e.g. know how to find (analytically) MT states that are very far apart. But to my knowledge no such equation has been derived. But often in Monte Carlo simulations, the PRNG is not the dominant computational bottleneck. So we can simply start N PRNGs from N consequtive states, and for each PRNG only use every N-th pseudorandom deviate. OK, now I understand. In my application I don't care about a thread's PRNG reaching the start of another threads. I do understand that this is not the case in all applications. -- http://mail.python.org/mailman/listinfo/python-list
Re: Threading with queues
On Mon, Dec 21, 2009 at 3:24 PM, Stephen Hansen wrote: > This is indented over one indentation level too much. You want it to > be at the same level as the for above. Here, its at the same level > with "t" -- meaning this entire loop gets repeated five times. Err, "this" in this context meant the second for loop, if that wasn't obvious. Sorry. --S -- http://mail.python.org/mailman/listinfo/python-list
Re: numpy performance and random numbers
sturlamolden wrote: On 19 Des, 16:20, Carl Johan Rehn wrote: How about mulit-core or (perhaps more exciting) GPU and CUDA? I must admit that I am extremely interested in trying the CUDA-alternative. Obviously, cuBLAS is not an option here, so what is the safest route for a novice parallel-programmer? The problem with PRNG is that they are iterative in nature, and maintain global states. They are therefore very hard to vectorize. A GPU will not help. The GPU has hundreds of computational cores that can run kernels, but you only get to utilize one. Parallel PRNGs are an unsolved problem in computer science. My parallel version of ziggurat works fine, with Fortran/OpenMP. -- http://mail.python.org/mailman/listinfo/python-list
Re: numpy performance and random numbers
sturlamolden wrote: On 19 Des, 14:06, Carl Johan Rehn wrote: Matlab and numpy have (by chance?) the exact names for the same functionality, Common ancenstry, NumPy and Matlab borrowed the name from IDL. LabView, Octave and SciLab uses the name randn as well. So the basioc question is, how can I speed up random number generation? The obvious thing would be to compile ziggurat yourself, and turn on optimization flags for your hardware. http://www.jstatsoft.org/v05/i08/ P.S. Be careful if you consider using more than one processor. Multithreading is a very difficult issue with PRNGs, becuase it is difficult to guarrantee they are truely independent. But you can use a producer-consumer pattern, though: one thread constantly producing random numbers (writing into a buffer or pipe) and another thread(s) consuming them. In case you're interested, I've made a multi-thread version of ziggurat (actually in Fortran for use with OpenMP). It is a simple enough mod, there is an additional argument (thread number) in each call to the ziggurat functions, and ziggurat maintains separate variables for each thread (not just the seed). There was one non-trivial issue. To avoid cache collisions, the seed values (an array corresponding to jsr in the original code) need to be spaced sufficiently far apart. Without this measure the performance was disappointingly slow. I agree with your recommendation - ziggurat is really fast. -- http://mail.python.org/mailman/listinfo/python-list
Re: Threading with queues
On Mon, Dec 21, 2009 at 3:12 PM, Gib Bogle wrote: > #spawn a pool of threads, and pass them queue instance > for i in range(5): > t = ThreadUrl(queue,i) > t.setDaemon(True) > t.start() > > #populate queue with data > for host in hosts: > queue.put(host) This is indented over one indentation level too much. You want it to be at the same level as the for above. Here, its at the same level with "t" -- meaning this entire loop gets repeated five times. I sorta really recommend a tab width of 4 spaces, not 2 :) At 2, its _really_ hard (especially if you're newer to Python) to see these kinds of issues and since indentation is program logic and structure in Python, that's bad... especially since your comment is indented to the right level, but the code isn't :) --S -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows, IDLE, __doc_, other
On Mon, Dec 21, 2009 at 2:57 PM, W. eWatson wrote: > This has got to be some sort of IDLE issue then. Huh? How do you figure? > When I run a simple > program. If I open this program in the IDLE editor: > #import math > print "hello, math world." > print cos(0.5) > print sin(0.8) > > then I get > print cos(0.5) > NameError: name 'cos' is not defined Of course, because -- cos is not defined. As I stated in my previous email, "math" has to be imported to be used. > > OK, >>> dir() > ['__builtins__', '__doc__', '__file__', '__name__', 'idlelib'] > > Fine. I now change the code to include import mat get the same: > print cos(0.5) > NameError: name 'cos' is not defined Yes, because cos is inside math. [snip > Now, I go to the script and enter > from math import * > dir is now bulked up with the math functions. I change back math.cos to cos > and the program runs well. > > This sort of figures. Apparently, I've added to the namespace by importing > with *. Apparently? -- you precisely and explicitly added every object in 'math' to your current namespace. "from math import *" does precisely that. > My point is that I'm betting different results. OK, fine. It appears the > same thing happens with I modify the program itself with from math import * Different results? What different results are you talking about? If you want to access 'sin' without 'math.', you'll have to do 'from math import *' in each file where you want to do that. > So IDLE is not clearing the namespace each time I *run* the program. This is > not good. I've been fooled. So how do I either clear the namespace before > each Run? Do I have to open the file in the editor again each time before > trying to Run it? I hope there's a better way. How do you figure its 'not clearing the namespace'? In which namespace? I fire up IDLE, and start a new file, and put in a single line: "a = 1". I choose Run Module, and it runs it. I verify in the interactive interpreter that a is 1. I then change that file to "a = a + 1", and run it. Now, it errors out-- of course-- because IDLE "cleared" the namespace and re-ran the module. It says in the interpreter its restarting, even. --S -- http://mail.python.org/mailman/listinfo/python-list
Threading with queues
Hi, I'm learning Python, jumping in the deep end with a threading application. I came across an authoritative-looking site that recommends using queues for threading in Python. http://www.ibm.com/developerworks/aix/library/au-threadingpython/index.html The author provides example code that fetches data from several web sites, using threads. I have modified his code slightly, just adding a couple of print statements and passing an ID number to the thread. #!/usr/bin/env python import Queue import threading import urllib2 import time hosts = ["http://yahoo.com";, "http://google.com";, "http://amazon.com";, "http://ibm.com";, "http://apple.com";] queue = Queue.Queue() class ThreadUrl(threading.Thread): #"""Threaded Url Grab""" def __init__(self, queue,i): threading.Thread.__init__(self) self.queue = queue self.num = i print "Thread: ",self.num def run(self): while True: #grabs host from queue host = self.queue.get() print "num, host: ",self.num,host #grabs urls of hosts and prints first 1024 bytes of page url = urllib2.urlopen(host) print url.read(1024) #signals to queue job is done self.queue.task_done() start = time.time() def main(): #spawn a pool of threads, and pass them queue instance for i in range(5): t = ThreadUrl(queue,i) t.setDaemon(True) t.start() #populate queue with data for host in hosts: queue.put(host) #wait on the queue until everything has been processed queue.join() main() print "Elapsed Time: %s" % (time.time() - start) Executed on Windows with Python 2.5 this program doesn't do what you want, which is to fetch data from each site once. Instead, it processes the first host in the list 5 times, the next 4 times, etc, and the last just once. I don't know whether it is a case of the code simply being wrong (which seems unlikely), or the behaviour on my system being different from AIX (also seems unlikely). Naively, I would have expected the queue to enforce processing of its members once only. Is there a simple change that will make this code execute as required? Or is this author out to lunch? Cheers Gib -- http://mail.python.org/mailman/listinfo/python-list
Re: C Structure rebuild with ctypes
Hi Mark,
many thanks for your help. I tried your code in my program and it worked.
I would like to understand what the code is doing and I have some questions
to it.
> Are you passing in these values, or are they being returned? To me the
> depth of the pointer references implies numVars, varNames, and varTypes
> are out parameters. I'll assume that for now. If they are in/out
> parameters let me know.
Your exactly right: the parameters numVars, varNames and VarTypes are out
paramters.
> I mocked up a DLL to test returning values of these types. I used VS2008
> and compiled with "cl /LD func.c":
>
> --- func.c ---
> #include
> #define FUNCDLL
> #include "func.h"
>
> static char* g_data[] = {"one","two","three"};
> static int g_types[] = {1,2,3};
>
> FUNCAPI int func (int handle, int *numVars, char ***varNames, int
> **varTypes)
> {
> *numVars = _countof(g_data);
> *varNames = g_data;
> *varTypes = g_types;
> return handle + 1;
> }
What does the signature FUNCAPI do in this context?
>
>
> --- func.h ---
> #ifdef FUNCDLL
> #define FUNCAPI __declspec(dllexport)
> #else
> #define FUNCAPI __declspec(dllimport)
> #endif
>
> FUNCAPI int func (int handle, int *numVars, char ***varNames, int
> **varTypes);
>
Do I need to wrap the compiled DLL file this way? I can load the DLL with
the CDLL method, make calls to simple functions, e.g. no parameters,
returning stirng and get the right values.
I added all the code from your func.py module to the code I already had.
And -- it works fine and delivers the expected results.
> --- func.py ---
... cut ...
>
> # int func (int handle, int *numVars, char ***varNames, int **varTypes)
> func = c.CDLL('func').func
> func.restype = INT
> func.argtypes = [INT,PINT,PPPCHAR,PPINT]
I added this part to my program.
> # allocate storage for the out parameters
> numVars = INT()
> varNames = PPCHAR()
> varTypes = PINT()
I added this part also.
> print func(5,c.byref(numVars),c.byref(varNames),c.byref(varTypes))
I called the library routine.
> # numVars contains size of returned arrays. Recast to access.
> varNamesArray = c.cast(varNames,c.POINTER(PCHAR * numVars.value))
> varTypesArray = c.cast(varTypes,c.POINTER(INT * numVars.value))
What does this cast? How do I know how I have to cast the objects returned
from the library function?
What kind of objects do I get? I learned that the values of objects created
by the ctypes module are accessed using object.value?
Best regards
Georg
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Re: Windows, IDLE, __doc_, other
Stephen Hansen wrote: On Mon, Dec 21, 2009 at 1:51 PM, W. eWatson wrote: Lie Ryan wrote: On 12/22/2009 6:39 AM, W. eWatson wrote: Wow, did I get a bad result. I hit Ctrl-P, I think instead of Alt-P, and No, its not true. A built-in module does not mean its available everywhere. It means its built into Python itself-- e.g., its directly linked into the python dll and not a separate file (like most of the the standard library). Lots of modules are built-in, but they don't pollute the __builtins__ / universal namespace. You import them to access them. If you want you can "from math import *" if you want the math module to fill out your module namespace (I don't recommend *'s personally, its better to import symbols explicitly by name) --S This has got to be some sort of IDLE issue then. When I run a simple program. If I open this program in the IDLE editor: #import math print "hello, math world." print cos(0.5) print sin(0.8) then I get print cos(0.5) NameError: name 'cos' is not defined OK, >>> dir() ['__builtins__', '__doc__', '__file__', '__name__', 'idlelib'] Fine. I now change the code to include import mat get the same: print cos(0.5) NameError: name 'cos' is not defined Now, >>> dir() ['__builtins__', '__doc__', '__file__', '__name__', 'idlelib', 'math'] >>> math is now available. so I change cos(0.5) to math.cos(0.5) and get print sin(0.8) NameError: name 'sin' is not defined Fine, it needs math. dir() is the same. Now, I go to the script and enter from math import * dir is now bulked up with the math functions. I change back math.cos to cos and the program runs well. This sort of figures. Apparently, I've added to the namespace by importing with *. My point is that I'm betting different results. OK, fine. It appears the same thing happens with I modify the program itself with from math import * So IDLE is not clearing the namespace each time I *run* the program. This is not good. I've been fooled. So how do I either clear the namespace before each Run? Do I have to open the file in the editor again each time before trying to Run it? I hope there's a better way. -- http://mail.python.org/mailman/listinfo/python-list
Re: numpy performance and random numbers
sturlamolden wrote: > On 19 Des, 16:20, Carl Johan Rehn wrote: > >> How about mulit-core or (perhaps more exciting) GPU and CUDA? I must >> admit that I am extremely interested in trying the CUDA-alternative. >> >> Obviously, cuBLAS is not an option here, so what is the safest route >> for a novice parallel-programmer? > > The problem with PRNG is that they are iterative in nature, and > maintain global states. They are therefore very hard to vectorize. A > GPU will not help. The GPU has hundreds of computational cores that > can run kernels, but you only get to utilize one. > > Parallel PRNGs are an unsolved problem in computer science. > > > > > Surely you could have as many totally independent cores as you like independently spitting out random bits whenever they feel like it to make an equally random bitstream? would have thought the only issue would be ensuring high quality bitstream was used to seed each thread no? Roger. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to register with pypi
Martin v. Loewis wrote: I'm stuck on the "PGP Key ID". When I whip out my trusty Ubuntu and run pgp -kg, I get a 16-digit "DSA / EIGamal" key. When I enter it into http://pypi.python.org/pypi?%3Aaction=register_form , I get a helpful "PGP Key ID is invalid". Should I try a key of some other algorithm? If you merely try to register with PyPI, you don't need to provide a PGP key id at all. I want to upload a crypto library I invented. That's a joke. But I want to upload a library. The key ID should be an eight-digit string, such as EA5BBD71 (i.e. a 32-bit key ID). pretend I was someone who had never ever used PGP before. pgp -kg, then what? -- http://mail.python.org/mailman/listinfo/python-list
Re: how to register with pypi
> I'm stuck on the "PGP Key ID". When I whip out my trusty Ubuntu and run > pgp -kg, I get a 16-digit "DSA / EIGamal" key. > > When I enter it into http://pypi.python.org/pypi?%3Aaction=register_form > , I get a helpful "PGP Key ID is invalid". > > Should I try a key of some other algorithm? If you merely try to register with PyPI, you don't need to provide a PGP key id at all. The key ID should be an eight-digit string, such as EA5BBD71 (i.e. a 32-bit key ID). Regards, Martin -- http://mail.python.org/mailman/listinfo/python-list
ANN: logbuilder 0.1.0a
This is a one-time post to annouce the creation of logbuilder project, an open source tool for change log creation based on version control commit messages. Using conventions in commit messages logbuilder detects messages that can be imported into the change log and painlessly creates on for every version of software. Home page: http://code.google.com/p/logbuilder/ Features: * Subersion support * Mercurial support * Filtering using wildcards, regular expressions and string matching * (planned) Using templates for displaying results Requirements: * Python 2.6+ * pysvn or mercurial For more information, please come to http://code.google.com/p/logbuilder/. -- Filip Gruszczyński -- http://mail.python.org/mailman/listinfo/python-list
Re: Class variables static by default?
On Mon, 21 Dec 2009 15:03:03 +0100, Daniel Fetchinson wrote: > I don't think Steven cares much, he loves this type of nitpicking and > uber pedantic formulations, but only if he can apply it to other > people's post :) Heh heh :) I actually do care, because (not having a Java/C++ background) I actually do get a mental "double-take" every time I read about "class variables". It takes a real effort of will to remind myself that they're probably not talking about something like this: for theclass in (int, float, Decimal, Fraction): do_something_with(theclass) > I found that his posts are generally useful and helpful, one just has to > cut all the nitpicking, ... Technically you don't have to cut *all* the nitpicking, cutting 87.3% of it is sufficient. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: How to validate the __init__ parameters
On 12/22/2009 4:41 AM, Denis Doria wrote: Hi; I'm checking the best way to validate attributes inside a class. Of course I can use property to check it, but I really want to do it inside the __init__: class A: def __init__(self, foo, bar): self.foo = foo #check if foo is correct self.bar = bar A nice sugar to do that: import functools class CheckError(Exception): pass def func_check(*argcheckers): def _checked(func): def _function(*args): res = [(check(arg), check, arg) for check, arg in zip(argcheckers, args)] if all(r[0] for r in res): return func(*args) else: raise CheckError(filter(lambda x: x[0] == False, res)) return _function return _checked method_check = functools.partial(func_check, lambda a: True) ## def check_foo(arg): return 5 <= arg <= 10 def check_bar(arg): return 10 <= arg < 20 class A(object): @method_check(check_foo, check_bar) def __init__(self, foo, bar): self.foo = foo self.bar = bar -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows, IDLE, __doc_, other
On Mon, Dec 21, 2009 at 1:51 PM, W. eWatson wrote: > Lie Ryan wrote: >> >> On 12/22/2009 6:39 AM, W. eWatson wrote: >>> >>> Wow, did I get a bad result. I hit Ctrl-P, I think instead of Alt-P, and >>> a little window came up showing it was about to print hundreds of pages. >>> I can canceled it, but too late. I turned off my printer quickly and >>> eventually stopped the onslaught. >>> >>> I couldn't get Alt-P or N to work. >>> >>> Another question. In interactive mode, how does one know what modules >>> are active? Is there a way to list them with a simple command? >> >> What do you mean by "active"? All loaded modules, whether it is in your >> namespace or not? Then sys.modules. >> Else if you want all names in your namespace, dir() would do, though it'll >> show other things as well. > > Let's forget active. Isn't it true that math is automatically available to > every module? From help(math): No, its not true. A built-in module does not mean its available everywhere. It means its built into Python itself-- e.g., its directly linked into the python dll and not a separate file (like most of the the standard library). Lots of modules are built-in, but they don't pollute the __builtins__ / universal namespace. You import them to access them. If you want you can "from math import *" if you want the math module to fill out your module namespace (I don't recommend *'s personally, its better to import symbols explicitly by name) --S -- http://mail.python.org/mailman/listinfo/python-list
Re: Line indexing in Python
seafoid wrote:
> Hi Guys,
>
> When python reads in a file, can lines be referred to via an index?
>
> Example:
>
> for line in file:
> if line[0] == '0':
> a.write(line)
>
> This works, however, I am unsure if line[0] refers only to the first line or
> the first character in all lines.
>
> Is there an easy way to refer to a line with the first character being a
> single letter that you know?
>
> Thanks in advance,
> Seafoid.
If you want to know the index number of an item in a sequence you are
looping through (whether it be a file of lines or a list of characters,
whatever) use enumerate...
>>> for index, value in enumerate("ABCD"):
print index, value
...
0 A
1 B
2 C
3 D
If you want to extract an index number from the first part of of a given
line use split( split_character, maximum_splits_to_do ) and then angle
brackets to reference the first part (index 0)...
>>> a = "20 GOTO 10"
>>> int( a.split(' ',1)[0] )
20
Cheers,
Roger.
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Re: converting string to a date format
tekion writes:
> Ben,
> I do not have python 2.6 install, my version of Python is 2.4.
Ouch :-( Upgrade as soon as possible, 2.4 is no longer receiving bug
fixes http://www.python.org/download/releases/2.4.6/>.
> So I guess I am stuck on parsing the string "24/Nov/2009:12:00:00
> -0500" using regex and or string function
No, as I suggested, you can use the ‘datetime.datetime’ constructor with
the ‘time.strptime’ output. You only have available the formatting in
http://docs.python.org/library/time.html#time.strftime>, so the
numeric time zone will be un-parseable by ‘time.strptime’::
>>> import datetime
>>> import time
>>> in_text = "24/Nov/2009:12:00:00 -0500"
>>> in_time_format = "%d/%b/%Y:%H:%M:%S %Z"
>>> time.strptime(in_text, in_time_format)
Traceback (most recent call last):
File "", line 1, in ?
File "/usr/lib/python2.4/_strptime.py", line 293, in strptime
raise ValueError("time data did not match format: data=%s fmt=%s" %
ValueError: time data did not match format: data=24/Nov/2009:12:00:00
-0500 fmt=%d/%b/%Y:%H:%M:%S %Z
Instead you'll need to do as has already been suggested: strip the
numeric time zone and parse the remaining data::
>>> in_text = "24/Nov/2009:12:00:00 -0500".split(' ', 1)[0]
>>> in_text
'24/Nov/2009:12:00:00'
>>> in_time_format = "%d/%b/%Y:%H:%M:%S"
>>> time.strptime(in_text, in_time_format)
(2009, 11, 24, 12, 0, 0, 1, 328, -1)
and use the hack documented in Python 2.6's ‘datetime.datetime.strptime’
function to create a ‘datetime’ object::
>>> in_time = datetime.datetime(*(time.strptime(in_text,
in_time_format)[0:6]))
>>> in_time
datetime.datetime(2009, 11, 24, 12, 0)
The benefit of upgrading to Python 2.6 is that you don't need to go
through these contortions with the ‘time’ type's output, you can use the
new ‘datetime.datetime.strptime’ method to get there in one step
http://docs.python.org/library/datetime.html#datetime.datetime.strptime>.
> to get the output to "2009-11-24 12:00:00".
Once you have a ‘datetime’ object, you can use its ‘strftime’ function
http://docs.python.org/library/datetime.html#strftime-behavior> to
create a string representation::
>>> out_time_format = "%Y-%m-%d %H:%M:%S"
>>> in_time.strftime(out_time_format)
'2009-11-24 12:00:00'
--
\ “I find the whole business of religion profoundly interesting. |
`\ But it does mystify me that otherwise intelligent people take |
_o__)it seriously.” —Douglas Adams |
Ben Finney
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Re: converting string to a date format
On Dec 21, 3:05 pm, MRAB wrote:
> tekionwrote:
> > Ben,
> > I do not have python 2.6 install, my version of Python is 2.4.
> > Because of my version of Python I believe I have to perform what you
> > have suggested:
>
> > This should, ideally, consist of two separate operations:
>
> > * parse the string, using a specific format, to create a ‘datetime’
> > object
>
> > * create a string representation of the datetime using your
> > preferred
> > string format
>
> > So I guess I am stuck on parsing the string "24/Nov/2009:12:00:00
> > -0500" using regex and or string function to get the output to
> > "2009-11-24 12:00:00". It looks like I may have to use regex to
> > accomplish this and also re-map Nov to "11". Does any one have any
> > idea that would take "24/Nov/2009:HH:MM:SS" and format it to
> > "2009-11-24 HH:MM:SS"? Thanks
>
> If you don't have the 'datetime' module then you can use the 'time'
> instead. Use time.strptime() to parse the string and time.strftime() to
> create the new string.
Thanks. This is what I have:
time.strftime("%Y-%m-%d %H:%M:%S", time.strptime("24/Nov/
2009:12:00:00", "%d/%b/%Y:%H:%M:%S")
and it seems to work.
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Re: Windows, IDLE, __doc_, other
Lie Ryan wrote: On 12/22/2009 6:39 AM, W. eWatson wrote: Wow, did I get a bad result. I hit Ctrl-P, I think instead of Alt-P, and a little window came up showing it was about to print hundreds of pages. I can canceled it, but too late. I turned off my printer quickly and eventually stopped the onslaught. I couldn't get Alt-P or N to work. Another question. In interactive mode, how does one know what modules are active? Is there a way to list them with a simple command? What do you mean by "active"? All loaded modules, whether it is in your namespace or not? Then sys.modules. Else if you want all names in your namespace, dir() would do, though it'll show other things as well. Let's forget active. Isn't it true that math is automatically available to every module? From help(math): Help on built-in module math: NAME math FILE (built-in) DESCRIPTION This module is always available. It provides access to the mathematical functions defined by the C standard. = So why do I need math.cos(...)? This is got to be some namespace issue. Maybe the help is incorrect. I have: >>> dir(__builtins__) ['ArithmeticError', 'AssertionError', 'AttributeError', 'BaseException', 'DeprecationWarning', 'EOFError', 'Ellipsis', 'EnvironmentError', 'Exception', 'False', 'FloatingPointError', 'FutureWarning', 'GeneratorExit', 'IOError', 'ImportError', 'ImportWarning', 'IndentationError', 'IndexError', 'KeyError', 'KeyboardInterrupt', 'LookupError', 'MemoryError', 'NameError', 'None', 'NotImplemented', 'NotImplementedError', 'OSError', 'OverflowError', 'PendingDeprecationWarning', 'ReferenceError', 'RuntimeError', 'RuntimeWarning', 'StandardError', 'StopIteration', 'SyntaxError', 'SyntaxWarning', 'SystemError', 'SystemExit', 'TabError', 'True', 'TypeError', 'UnboundLocalError', 'UnicodeDecodeError', 'UnicodeEncodeError', 'UnicodeError', 'UnicodeTranslateError', 'UnicodeWarning', 'UserWarning', 'ValueError', 'Warning', 'WindowsError', 'ZeroDivisionError', '_', '__debug__', '__doc__', '__import__', '__name__', 'abs', 'all', 'any', 'apply', 'basestring', 'bool', 'buffer', 'callable', 'chr', 'classmethod', 'cmp', 'coerce', 'compile', 'complex', 'copyright', 'credits', 'delattr', 'dict', 'dir', 'divmod', 'enumerate', 'eval', 'execfile', 'exit', 'file', 'filter', 'float', 'frozenset', 'getattr', 'globals', 'hasattr', 'hash', 'help', 'hex', 'id', 'input', 'int', 'intern', 'isinstance', 'issubclass', 'iter', 'len', 'license', 'list', 'locals', 'long', 'map', 'max', 'min', 'object', 'oct', 'open', 'ord', 'pow', 'property', 'quit', 'range', 'raw_input', 'reduce', 'reload', 'repr', 'reversed', 'round', 'set', 'setattr', 'slice', 'sorted', 'staticmethod', 'str', 'sum', 'super', 'tuple', 'type', 'unichr', 'unicode', 'vars', 'xrange', 'zip'] -- http://mail.python.org/mailman/listinfo/python-list
Re: How to validate the __init__ parameters
On Mon, 21 Dec 2009 09:41:22 -0800, Denis Doria wrote:
> Hi;
>
> I'm checking the best way to validate attributes inside a class.
There is no "best way", since it depends on personal taste.
> Of
> course I can use property to check it, but I really want to do it inside
> the __init__:
If you "really want to do it inside the __init__", then copy the code
that you would put in the property's setter into the __init__ method. But
why do you care that the check is inside the __init__ method? All that is
really important is that the __init__ method *calls* the check, not where
the check lives.
> class A:
> def __init__(self, foo, bar):
> self.foo = foo #check if foo is correct
> self.bar = bar
Here are some ways of doing this, more or less in order of complexity and
difficulty.
(1) Don't validate at all. Just document that foo must be no more than
five characters long, and if the caller pays no attention and passes a
too-long string, any explosions that happen are their fault, not yours.
class A:
"""Class A does blah blah.
If foo is longer than five characters, behaviour is undefined.
"""
def __init__(self, foo = None, bar = None):
self.foo = foo
self.bar = bar
(This may seem silly, but for more difficult constraints which are hard
to test, it may be your only choice.)
(2) Validate once only, at initialisation time:
class A:
def __init__(self, foo = None, bar = None):
if len(foo) > 5:
raise ValueError("foo is too big")
self.foo = foo
self.bar = bar
Note that further assignments to instance.foo will *not* be validated.
(3) Move the validation into a method. This is particularly useful if the
validation is complex, or if you expect to want to over-ride it in a sub-
class.
class A:
def __init__(self, foo = None, bar = None):
self.validate(foo)
self.foo = foo
self.bar = bar
def validate(self, foo):
if len(foo) > 5:
raise ValueError("foo is too big")
Further assignments to instance.foo are still not validated.
(4) Validate on every assignment to foo by using a property. Note that
for this to work, you MUST use a new-style class. In Python 3, you don't
need to do anything special, but in Python 2.x you must inherit from
object:
class A(object):
def __init__(self, foo = None, bar = None):
self.foo = foo # calls the property setter
self.bar = bar
def _setter(self, foo):
if len(foo) > 5:
raise ValueError("foo is too big")
self._foo = foo
def _getter(self):
return self._foo
foo = property(_getter, _setter, None, "optional doc string for foo")
If you think this looks "too much like Java", well, sorry, but that's
what getters and setters look like. But note that you never need to call
the getter or setter explicitly, you just access instance.foo as normal.
(5) Use explicit Java-style getter and setter methods. This avoids using
property, so it doesn't need to be a new-style class:
class A:
def __init__(self, foo = None, bar = None):
self.setfoo(foo)
self.bar = bar
def setfoo(self, foo):
if len(foo) > 5:
raise ValueError("foo is too big")
self._foo = foo
def getfoo(self):
return self._foo
If you want to write Java using Python syntax, this may be the solution
for you. But be aware that Python programmers will laugh at you.
(5) If the constraint on foo is significant enough, perhaps it should be
made part of the type of foo.
class FooType(str): # or inherit from list, or whatever...
def __init__(self, x):
if len(x) > 5:
raise ValueError("initial value is too big, invalid FooType")
class A:
def __init__(self, foo = None, bar = None):
self.foo = FooType(foo)
self.bar = bar
Other, more complex solutions include using decorators or even metaclass
programming. Don't worry about these at this point, I'm just showing off
*wink*
Hope this helps,
--
Steven
--
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Re: How to validate the __init__ parameters
Denis Doria wrote:
> Hi;
>
> I'm checking the best way to validate attributes inside a class. Of
> course I can use property to check it, but I really want to do it
> inside the __init__:
>
> class A:
> def __init__(self, foo, bar):
> self.foo = foo #check if foo is correct
> self.bar = bar
>
> All examples that I saw with property didn't show a way to do it in
> the __init__. Just to clarify, I don't want to check if the parameter
> is an int, or something like that, I want to know if the parameter do
> not use more than X chars; and want to do it when I'm 'creating' the
> instance; not after the creation:
>
> a = A('foo', 'bar')
>
> not
>
> class A:
> def __init__(self, foo = None, bar = None):
> self._foo = foo
> self._bar = bar
> def set_foo(self, foo):
> if len(foo) > 5:
> raise
> _foo = foo
> foo = property(setter = set_foo)
>
> a = A()
> a.foo = 'foo'
>
>
> I thought in something like:
>
> class A:
> def __init__(self, foo = None, bar = None):
> set_foo(foo)
> self._bar = bar
> def set_foo(self, foo):
> if len(foo) > 5:
> raise
> _foo = foo
> foo = property(setter = set_foo)
>
> But looks too much like java
I use assertions myself e.g.
>>> foo = "123456"
>>> assert len(foo) <= 5
Traceback (most recent call last):
File "", line 1, in
AssertionError
Dunno if this would be considered good or bad programming practice by
those more experienced than I (comment always welcome!) but it works for
me :)
Roger.
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Re: Ch 3 of my writings, first few sections posted
This is an introduction to programming based on Python 3.x in Windows. It's posted as PDFs on Google Docs. Currently 2 full chapters plus a little of chapter 3, about 120 pages in total; chapters 1 and 2 reviewed by [comp.programming] and [comp.lang.python] residents (although I have no doubt that there are many errors etc., all mine!). * Alf P. Steinbach, in [comp.lang.python]: Tentatively titled "Foundations". Also, these first 2/3 sections may be moved to some later point, i.e. even the structure is tentative, but I'd value comments! http://tinyurl.com/programmingbookP3> Table of contents: 3 Foundations 1 3.1 Some necessary math notation & terminology. 2 3.1.1 The vocabulary and notation of basic arithmetic, including Σ and Π. 2 3.1.2 Quadratic and exponential time & memory (also introducing timeit). 5 -EOT_ 9 Cheers, - Alf PS: Hm, Open Office's PDF generation does funny things with Greek sigmas inside formulas! I don't mind so much that it makes table divider lines very fat and bold and that it can't handle certain figures (which I have to paste in manually as bitmaps), but really it should be able to handle simple text. Grr. I forgot to cross-post this to [comp.programming], the quoted article above was only posted to [comp.lang.python]. I now cross-posted it also to [comp.lang.c++]. I know, it's a bit OT in clc++, but it makes a nice contrast, and can be relevant for all those threads about "how do I learn programming"... And I've now posted an updated and full table of contents to Google Docs site, URL above. Comments very welcome -- now it's Christmas and I'll probably not be able to respond or fix anything until early January, but still comments very welcome! Cheers, - Alf PS: For clc++: why did I give up writing a beginner's book based on C++? Well, for one, in C++ it got too complicated and long the way I wanted it, "real". And secondly, Francis, Andrew & Barbara and Bjarne have by now got that covered! PPS: Also for clc++: where is my C++ tutorial, referenced from the FAQ (§29.21)? Well, first it moved to another URL, since [start.no] discontinued their service. Then that new free provider ceased to exist, so that now it's nowhere, and I've forgotten all about it. And probably will, yet again! I've CC-ed this to Marshall Cline so that perhaps he can update the FAQ to e.g. [http://cplusplus.com/doc/tutorial/], which by now is, well, acceptable quality! -- http://mail.python.org/mailman/listinfo/python-list
RotatingFileHandler key error when parsing a logging config file
Hi,
I've a config for logging where I set up a file rotation with
handlers.RotatingFileHandler and when the app parses the logging
config it says keyError when trying to parse that section
('RotatingFileHandler' is not defined). Curiously enough, I can do
import logging and from logging.handlers import RotatingFileHandler.
Example:
[handlers]
keys=handlers.RotatingFileHandler
[formatters]
keys=simpleFormatter
[logger_root]
level=DEBUG
handlers=handlers.RotatingFileHandler
[handler_handlers.RotatingFileHandler]
class=handlers.RotatingFileHandler
level=DEBUG
formatter=simpleFormatter
I'm using python 2.4 in the servers. I'm having this in a particular
one, which seems like there must be some kind of configuration error.
Any suggestions,
Thanks
--
http://mail.python.org/mailman/listinfo/python-list
Re: Windows, IDLE, __doc_, other
On 12/22/2009 6:39 AM, W. eWatson wrote: Wow, did I get a bad result. I hit Ctrl-P, I think instead of Alt-P, and a little window came up showing it was about to print hundreds of pages. I can canceled it, but too late. I turned off my printer quickly and eventually stopped the onslaught. I couldn't get Alt-P or N to work. Another question. In interactive mode, how does one know what modules are active? Is there a way to list them with a simple command? What do you mean by "active"? All loaded modules, whether it is in your namespace or not? Then sys.modules. Else if you want all names in your namespace, dir() would do, though it'll show other things as well. -- http://mail.python.org/mailman/listinfo/python-list
Re: Which version of MSVC?90.DLL's to distribute with Python 2.6 based Py2exe executables?
Jonathan Hartley wrote: >Many thanks for that, but my issue is that my programs work fine for >me on my computer - but then fail on other people's computers. I'd >very strongly prefer for my users to not have to install the MSVCR >redistributable installer as well as my program - it would be much >better if I could bundle everything up into my py2exe package so that >it 'just works' on any Windows computer. So I think that means I'm >looking for a stand-alone DLL (or several, plus the manifest file, it >sounds like) to bundle up with my py2exe. Microsoft's documentation describes several possible ways you can redistribute the Visual C++ runtime: http://msdn.microsoft.com/en-us/library/ms235299.aspx >From the sounds of things, if you only have Visual C++ 2008 Express your only option may be to use Visual C++ Redistributable Package. Ross Ridge -- l/ // Ross Ridge -- The Great HTMU [oo][oo] rri...@csclub.uwaterloo.ca -()-/()/ http://www.csclub.uwaterloo.ca/~rridge/ db // -- http://mail.python.org/mailman/listinfo/python-list
Re: Which version of MSVC?90.DLL's to distribute with Python 2.6 based Py2exe executables?
On Dec 17, 11:16 pm, Mark Hammond wrote: > On 18/12/2009 7:44 AM, Ross Ridge wrote: > > > The "P" DLL is for C++ and so the original poster may not actually need > > it. I'm pretty sure Python itself doesn't need it, and py2exe shouldn't > > either, but wxPython, or more precisely wxWidgets, almost certainly does. > > So in your case you'll probably need to redistribute both DLLs. > > FYI, my experience is that an entire manifest must be distributed. As > the manifest in question actually lists 3 DLLs, IIUC, you must ship all > 4 files - the 3 DLLs and the manifest, even if only one of the DLLs is > actually used. > > This is from memory some time back though, so apologies in advance if > I'm mis-remembering. > > Mark Thanks to everyone who replied, especially Ross obviously for such comprehensive info. I'll go percolate on what you wrote, and try some experiments on my new VM, see if it all makes sense for me when I put it into practice. -- http://mail.python.org/mailman/listinfo/python-list
Re: Anybody use web2py?
On Dec 21, 2:50 am, Bruno Desthuilliers wrote: > mdipierro a écrit : ... > > This means you do not need to import > > basic web2py symbols. They are already defined in the environment that > > executes the models and controllers > > Ok. As far as I'm concerned : show stops here. Sorry- I don't _think_ I'm following: If you want to write an app all yourself, and use components to put it together, that's fine - more control, and more responsibility (e.g. watch for security, etc.). But most web applications simply do not require or justify this much effort spent on this level of "responsibility"; but maybe I'm missing something less obvious that you mean, that makes "the show stop here" for you. If so, maybe you can be a bit more explicit about it. > > > - You have a web based IDE with editor, > > Why should I care ? I have a way better development environment on my > own box. > For example, on a running system, simple things are possible simply: change the cutoff date on something; change a class size. Yeah, sure - my app could write a controller for all those _little_ unanticipated tweaks that inevitably come, but why bother? You can just do it with existing environment: Want 100 coupons for that vendor? No problem (lets say that's in a controller). Want to make it a special thingy for that special vendor - put his image on his coupons? his words and instructions? Ok - I suppose i might have written a wiki interface so someone can do this one thing, this one time - but (again) why bother? I'll do it thru the dev. interface on a running system. If I'm convinced it was an un-captured requirement (e.g. no one thought of it until the system was running, or it was "assumed" but somehow missed by everyone) then I'll write the associated code, and add it to the running system. In fact, this is quite an agile way to do it. Both the dev. environ, and the command line shell help in this (I can write a small loop in the shell to effect what might be a controller for a customer, and output to a file instead of a view, and ask the customer "Is this what you're looking for?" - tweak, confirm happy client, and then put the code I just used into a controller - if it's short enough, right in the interface on the running system, and have the client try it while we're still on the phone/IM/whatever. The things I didn't think would be that useful - proved to have useful application. .. > > Now FWIW, when my schema do change, the create/alter table code is > usually the most trivial part - there are quite a few other things to > do, that no framework will ever be abale to guess. IOW, you *do* have to > write a migration script anyway. In practice, this is /should be much less than you would think... ADDING columns to tables is simple. REMOVING columns... perhaps unnecessary on running systems... ALTERING columns... can probably be handled instead by adding. I think for most useful (and certain development time) cases, the framework can do reasonable things, usefully. But I do not deny that there are cases where there is not way around doing things smarter than that. I think it is just that there are times where that is not as necessary as at first appears. . > > Once again, while doing a quick dummy test app can give you a first > general "feel" of the tool, it means nothing wrt/ complex real-world > applications. Actually, I agree - and I would go a bit further: NO FRAMEWORK / tool has anything much to do wrt/ complex real-world apps. In fact, at the framework / coding level, things should be as simple as possible (that is where the cost is, anyway). Good analysis of the problem domain will suggest the shape of the solution needed. Prototyping will then help with things like "can it be a web app?" and "what technologies / implementation languages are appropriate?" Once you're at that stage, _any tool_ (and most likely, combination of tools / set of tools) come into play: what do they do to help at this level, how do they enable the process you want to follow, how do they get out of the way. Are they too rigid (too many defaults / too few options for a given solution decision)? But this is so far down the path of designing a solution that "complex real-world" doesn't fitthis discussion, without getting more specific, e.g. _a_ specific real-world app. For PyCon, web2py registration was done, reviewed, and put into place with little more than a month's worth of discussion / prep. Yeah, it didn't "look" like the main PyCon site the first year (and didn't take much at all to change that when I decided to). Yeah, there are still details about integrating w/ the django part of the site that could be taken care of from the web2py end (I don't know, but was lead to believe it would be easier from the web2py end than the django end, e.g. multiple database connections). As with many projects, if it is volunteer programming, and if it's _really_ important, it will happen, or if so
Re: which pi formula is given in the decimal module documentation?
In article ,
Albert van der Horst wrote:
>In article ,
>Mark Dickinson wrote:
>>On Dec 11, 10:30=A0am, Mark Dickinson wrote:
>>> > It looks like an infinite series with term `t`, where`n` =3D (2k-1)^2
>>> > and `d` =3D d =3D 4k(4k+2) for k =3D 1... Does it have a name?
>>>
>>> Interesting. =A0So the general term here is
>>> 3 * (2k choose k) / (16**k * (2*k+1)), =A0k >=3D 0.
>>>
>>> I've no idea what its name is or where it comes from, though. =A0I
>>> expect Raymond Hettinger would know.
>>
>>After a cup of coffee, it's much clearer: this just comes from the
>>Taylor series for arcsin(x), applied to x =3D 1/2 to get asin(1/2) =3D pi/
>>6.
>
>Curious. It seems better to calculate the zero of sin(pi/6)-1/2.
>Not that we can forego the need of a Taylor series, but sin
>converges much faster than arcsin.
>The derivative is known analytically, and we have a 5th order process
>before we know it.
>It would be a big win for large precisions.
>(Especially if we remember a previous value of pi to start up.)
>The trick with temporarily increasing precision could be superfluous.
>
>(I implemented this once in FORTRAN and was much disappointed that
>double precision wasn't enough to show off the 5th order convergence. )
>
>>--
>>Mark
>
>Groetjes Albert
What the heck. I tried it all out. It turns out that sin(pi/6)=.5
is not favourable because the derivative contains sqrt(3)
So I tried to find the zero of cos(x) near pi/2 which is pi/2.
The derivative of the cos is -sin. So a better approximation than
x is x+cos(x). The second derivative is cos which is zero.
The third derivative is again -cos(x).
So a still better approximation is x+cos(x)+cos(x)^3/6.
This can be iterated. [The remaining error is 3/40.cos(x)^5.
I found that experimentally and a proof is left to the reader.]
Below you see cos which just calculates cosine with a
Taylor series.
Then there is pi2() that uses it to calculate pi, for the
normal fp precision.
pi3() shows the algorithm in its glory and should work for
any floating point package.
pi4() does the same, if precision is given.
And last but not least pi5() that uses the Decimal package
to advantage. It precalculates a starting point in 1/5 of
the precision. Then it does one more iteration in the full precision.
For 1000 digits it is about 5 times faster than pi(), for
a moderate increase in complexity.
# --- 8<8<---
# $Id: pi.py,v 1.3 2009/12/21 19:01:15 albert Exp albert $
# Copyright (2008): Albert van der Horst {by GNU Public License}
#
from decimal import getcontext,Decimal
def pi():
"""Compute Pi to the current precision.
>>> print pi()
3.141592653589793238462643383
"""
getcontext().prec += 2 # extra digits for intermediate steps
three = Decimal(3) # substitute "three=3.0" for regular floats
lasts, t, s, n, na, d, da = 0, three, 3, 1, 0, 0, 24
while s != lasts:
print s
lasts = s
n, na = n+na, na+8
d, da = d+da, da+32
t = (t * n) / d
s += t
getcontext().prec -= 2
return +s # unary plus applies the new precision
def cos(halfpi):
"""Compute cos of halfpi
"""
x = halfpi**2
t = 1
lasts = 1
s = 0 # First term is actually 1
n=1
while s != lasts:
print s
lasts = s
t = -t*x / (n*(n+1))
n += 2
s += t
# Add 1 now, this saves iterations that don't contribute to precision.
return 1+s
def pi2():
' Calculate pi by a correction based on derivatives '
x=1.57
q=cos(1.57)
# Deviation 3/40.q^5
return 2*(x+q+q**3/6)
def pi3():
' Calculate pi by a 5th order process '
x=1.5
xold =1.
while x != xold:
xold = x
q = cos(x)
x += q*(1+q*q/6)
return 2*x
def pi4():
' Calculate pi by a 5th order process, with favorable stop criterion'
precision = 10e-20
rp = precision ** .2 # Required precision with room to spare.
print rp
x=1.5
q=1
while q>rp:
q = cos(x)
x += q*(1+q*q/6)
return 2*x
def pi5():
' Calculate pi by a 5th order process, adjusting precision'
oldprec = getcontext().prec
getcontext().prec = oldprec/4+1
rp = Decimal(10)**(-getcontext().prec+1)
x=Decimal("1.5")
q = x
while q >rp:
print x,q,rp
q = cos(x)
x += q*(1+q*q/6)
# One more iteration with full precision
getcontext().prec = oldprec + 2
q = cos(x)
x += q*(1+q*q/6)
getcontext().prec = oldprec
return 2*x
# --- 8<8<---
>
>--
>--
>Albert van der Horst, UTRECHT,THE NETHERLANDS
>Economic growth -- being exponential -- ultimately falters.
>alb...@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst
>
--
--
Albert van der Horst, UTRECHT,THE NETHERLANDS
Economic growth -- being exponential -- ultimately falters.
alb...@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m
Re: Which version of MSVC?90.DLL's to distribute with Python 2.6 based Py2exe executables?
On Dec 17, 8:39 pm, Christian Heimes wrote:
> Jonathan Hartley wrote:
> > Only this week I sent a py2exe-derived executable to someone else (a
> > non-developer) and it would not run on their WinXP machine ("'The
> > system cannot execute the specified program'") - my current favourite
> > hypothesis is that my omission of this dll or something similar was to
> > blame.
>
> > To diagnose what's wrong, I can't get access to the machine that gives
> > the above error. To try and reproduce, I'm right now in the process of
> > creating a bare-bones WindowsXP installed on a VM.
>
> MSVCR90 is a side-by-side assembly (SxS). You can't just copy a SxS
> assembly to another computer. You must at least ship the manifest file,
> too. The easiest way to get your program running is the installation of
> the MSVCR redistributable installer.
>
> Christian
Hey Christian,
Many thanks for that, but my issue is that my programs work fine for
me on my computer - but then fail on other people's computers. I'd
very strongly prefer for my users to not have to install the MSVCR
redistributable installer as well as my program - it would be much
better if I could bundle everything up into my py2exe package so that
it 'just works' on any Windows computer. So I think that means I'm
looking for a stand-alone DLL (or several, plus the manifest file, it
sounds like) to bundle up with my py2exe.
--
http://mail.python.org/mailman/listinfo/python-list
Re: converting string to a date format
tekion wrote: Ben, I do not have python 2.6 install, my version of Python is 2.4. Because of my version of Python I believe I have to perform what you have suggested: This should, ideally, consist of two separate operations: * parse the string, using a specific format, to create a ‘datetime’ object * create a string representation of the datetime using your preferred string format So I guess I am stuck on parsing the string "24/Nov/2009:12:00:00 -0500" using regex and or string function to get the output to "2009-11-24 12:00:00". It looks like I may have to use regex to accomplish this and also re-map Nov to "11". Does any one have any idea that would take "24/Nov/2009:HH:MM:SS" and format it to "2009-11-24 HH:MM:SS"? Thanks If you don't have the 'datetime' module then you can use the 'time' instead. Use time.strptime() to parse the string and time.strftime() to create the new string. -- http://mail.python.org/mailman/listinfo/python-list
ANN: eGenix mx Base Distribution 3.1.3
ANNOUNCING eGenix.com mx Base Distribution Version 3.1.3 for Python 2.3 - 2.6 Open Source Python extensions providing important and useful services for Python programmers. This announcement is also available on our web-site for online reading: http://www.egenix.com/company/news/eGenix-mx-Base-Distribution-3.1.3-GA.html ABOUT The eGenix.com mx Base Distribution for Python is a collection of professional quality software tools which enhance Python's usability in many important areas such as fast text searching, date/time processing and high speed data types. The tools have a proven record of being portable across many Unix and Windows platforms. You can write applications which use the tools on Windows and then run them on Unix platforms without change due to the consistent platform independent interfaces. Contents of the distribution: * mxDateTime - Date/Time Library for Python * mxTextTools - Fast Text Parsing and Processing Tools for Python * mxProxy - Object Access Control for Python * mxBeeBase - On-disk B+Tree Based Database Kit for Python * mxURL - Flexible URL Data-Type for Python * mxUID - Fast Universal Identifiers for Python * mxStack - Fast and Memory-Efficient Stack Type for Python * mxQueue - Fast and Memory-Efficient Queue Type for Python * mxTools - Fast Everyday Helpers for Python All available packages have proven their stability and usefulness in many mission critical applications and various commercial settings all around the world. For more information, please see the distribution page: http://www.egenix.com/products/python/mxBase/ NEWS The 3.1.3 release of the eGenix mx Base Distribution is the latest release of our open-source Python extensions. The new version addresses a serious problem with mxBeeBase on BSD-based platforms such as FreeBSD and Mac OS X. We encourage all users to upgrade to this new release. As always, we are providing pre-built binaries for all supported platforms: Windows 32-bit, Linux 32/64-bit, FreeBSD 32/64-bit, Mac OS X 32-bit Intel and PPC. Whether you are using a pre-built package or the source distribution, installation is a simple "python setup.py install" command in all cases. The only difference is that the pre-built packages do not require a compiler to be installed. For a list of changes, please refer to the eGenix mx Base Distribution change log at http://www.egenix.com/products/python/mxBase/changelog.html and the change logs of the various included Python packages. DOWNLOADS The download archives and instructions for installing the packages can be found on the eGenix mx Base Distribution page: http://www.egenix.com/products/python/mxBase/ LICENSE The eGenix mx Base package is distributed under the eGenix.com Public License 1.1.0 which is an Open Source license similar to the Python license. You can use the packages in both commercial and non-commercial settings without fee or charge. The package comes with full source code SUPPORT Commercial support for this product is available from eGenix.com. Please see http://www.egenix.com/services/support/ for details about our support offerings. Enjoy, -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Dec 21 2009) >>> Python/Zope Consulting and Support ...http://www.egenix.com/ >>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ >>> mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/ ::: Try our new mxODBC.Connect Python Database Interface for free ! eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 http://www.egenix.com/company/contact/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Live Video Capture using Python
David Lyon wrote: Also try.. http://www.unixuser.org/~euske/python/vnc2flv/index.html On Mon, 21 Dec 2009 11:15:32 +0530, Banibrata Dutta wrote: Have you searched the archives of this list ? I remember seeing a related discussion 5-6 months back. On Mon, Dec 21, 2009 at 2:35 AM, aditya shukla wrote: Hello Guys, I am trying to capture images from a live broadcast of a "cricket match" or say any video using python. I can see the video in the browser.My aim is to capture the video at any moment and create an images.Searching on google turns up http://videocapture.sourceforge.net/ .I am not sure if this would be help here.I would appreciate if someone points me in the right direction. Thanks Aditya -- http://mail.python.org/mailman/listinfo/python-list I somehow clipped the posts above this thread, so am not sure what prompted this thread. Is there an open source set of modules to do all this? -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows, IDLE, __doc_, other
Lie Ryan wrote: On 12/21/2009 1:19 PM, W. eWatson wrote: When I use numpy.__doc__ in IDLE under Win XP, I get a heap of words without reasonable line breaks. "\nNumPy\n=\n\nProvides\n 1. An array object of arbitrary homogeneous items\n 2. Fast mathematical operations over arrays\n 3. Linear Algebra, Fourier Transforms, Random Number Is there a way to get this formated properly. help(object) If I use dir(numpy), I get yet a very long list that starts as: ['ALLOW_THREADS', 'BUFSIZE', 'CLIP', 'DataSource', 'ERR_CALL', 'ERR_DEFAULT', 'ERR_DEFAULT2', 'ERR_IGNORE', 'ERR_LOG', 'ERR_PRINT', 'ERR_RAISE', 'ERR_WARN', 'FLOATING_POINT_SUPPORT', 'FPE_DIVIDEBYZERO', 'FPE_INVALID', 'FPE_OVERFLOW', 'FPE_UNDERFLOW', 'False_', 'Inf', 'Infinity', 'MAXDIMS', 'MachAr', 'NAN', 'NINF', 'NZERO', 'NaN', 'PINF', 'PZERO', 'PackageLoader', 'RAISE', 'RankWarning', 'SHIFT_DIVIDEBYZERO', 'SHIFT_INVALID', 'SHIFT_OVERFLOW', 'SHIFT_UNDERFLOW', 'ScalarType', 'Tester', 'True_', 'UFUNC_BUFSIZE_DEFAULT' I see this might be a dictionary. What can I do to make it more readable or useful, or is that it? Is there a more abc as in Linux? You can use pprint module: import pprint pprint.pprint(dir(object)) though help() is usually better It the IDLE shell, it's not possible to retrieve lines entered earlier without copying them. Is there an edit facility? Press Alt+P (Previous) and Alt+N (Next). Or you can click/select on the line you want to copy and press Enter. Add to this. Isn't there a way to see the arguments and descriptions of functions? Use help(). Or if you're doing this without human intervention, use `inspect` module. Wow, did I get a bad result. I hit Ctrl-P, I think instead of Alt-P, and a little window came up showing it was about to print hundreds of pages. I can canceled it, but too late. I turned off my printer quickly and eventually stopped the onslaught. I couldn't get Alt-P or N to work. Another question. In interactive mode, how does one know what modules are active? Is there a way to list them with a simple command? -- http://mail.python.org/mailman/listinfo/python-list
Re: converting string to a date format
Ben, I do not have python 2.6 install, my version of Python is 2.4. Because of my version of Python I believe I have to perform what you have suggested: This should, ideally, consist of two separate operations: * parse the string, using a specific format, to create a ‘datetime’ object * create a string representation of the datetime using your preferred string format So I guess I am stuck on parsing the string "24/Nov/2009:12:00:00 -0500" using regex and or string function to get the output to "2009-11-24 12:00:00". It looks like I may have to use regex to accomplish this and also re-map Nov to "11". Does any one have any idea that would take "24/Nov/2009:HH:MM:SS" and format it to "2009-11-24 HH:MM:SS"? Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: web development in python 2.6 and 3.0
On Mon, Dec 21, 2009 at 11:09 AM, Simon Moses wrote: > so python 2.6, mysql 5.0, apache 2.2, mod_wsgi, > MySQL-python-1.2.2.win32-py2.6 and Django should be sufficient for my > requirement. I don't know for certain; you're asking a bit too much specific detail here :) Just go to http://docs.djangoproject.com/en/dev/topics/install/ -- it shows you everything you need to install to get Django going :) --S -- http://mail.python.org/mailman/listinfo/python-list
Merging files into tar.gz archives
Hi, I am writing a script wherein I need to merge files into existing tar.gz archives. Currently, I am using tarfile module. I extract the tar.gz to a tempdir and copy the new file there and re-compress all the files back into a tar.gz. Is there a better way to do it? Thanks Pulkit (Sorry for the subject earlier) > -- http://mail.python.org/mailman/listinfo/python-list
Re: Python-list Digest, Vol 75, Issue 226
Hi, I am writing a script wherein I need to merge files into existing tar.gz files. Currently, I am using tarfile module. I extract the tar.gz to a tempdir and copy the new file there and re-compress all the files back into a tar.gz. Is there a better way to do it? Thanks Pulkit -- http://mail.python.org/mailman/listinfo/python-list
linking error after swig
Hi All, I have a mac os x, and I try to replicate the sample in swig tutorial but when I try to link, I have these linking errors: ld example.o example_wrap.o -o _example.so Undefined symbols: "_PyType_Type", referenced from: _PyType_Type$non_lazy_ptr in example_wrap.o "_PyExc_SystemError", referenced from: _PyExc_SystemError$non_lazy_ptr in example_wrap.o "_PyDict_New", referenced from: _SWIG_Python_NewShadowInstance in example_wrap.o _SWIG_Python_NewShadowInstance in example_wrap.o _SWIG_Python_SetSwigThis in example_wrap.o _SWIG_Python_TypeCache in example_wrap.o "_fputs$UNIX2003", referenced from: _PySwigObject_print in example_wrap.o _PySwigPacked_print in example_wrap.o _PySwigPacked_print in example_wrap.o "_PyExc_IOError", referenced from: _PyExc_IOError$non_lazy_ptr in example_wrap.o "_PyCObject_Import", referenced from: _SWIG_Python_GetModule in example_wrap.o "_PyList_Append", referenced from: _SWIG_Python_AppendOutput in example_wrap.o "_PyTuple_Type", referenced from: _PyTuple_Type$non_lazy_ptr in example_wrap.o "_PyExc_MemoryError", referenced from: _PyExc_MemoryError$non_lazy_ptr in example_wrap.o "_PyArg_ParseTuple", referenced from: __wrap_fact in example_wrap.o __wrap_my_mod in example_wrap.o __wrap_get_time in example_wrap.o "_strstr", referenced from: _SWIG_Python_ConvertFunctionPtr in example_wrap.o _SWIG_Python_FixMethods in example_wrap.o "_fwrite$UNIX2003", referenced from: _PySwigPacked_print in example_wrap.o _PySwigPacked_print in example_wrap.o _swig_varlink_print in example_wrap.o "_PyInstance_NewRaw", referenced from: _SWIG_Python_NewShadowInstance in example_wrap.o "_PyDict_SetItemString", referenced from: _SWIG_Python_SetConstant in example_wrap.o _SWIG_Python_InstallConstants in example_wrap.o _init_example in example_wrap.o "_PyFloat_AsDouble", referenced from: _SWIG_AsVal_double in example_wrap.o "_PyArg_UnpackTuple", referenced from: _PySwigObject_own in example_wrap.o "_PyObject_Str", referenced from: _SWIG_Python_AddErrorMsg in example_wrap.o _SWIG_Python_AddErrMesg in example_wrap.o _SWIG_Python_TypeError in example_wrap.o "_PyDict_GetItem", referenced from: _SWIG_Python_GetSwigThis in example_wrap.o _SWIG_Python_TypeQuery in example_wrap.o "_PyExc_TypeError", referenced from: _PyExc_TypeError$non_lazy_ptr in example_wrap.o "_PyString_FromString", referenced from: _PySwigObject_format in example_wrap.o _PySwigObject_str in example_wrap.o _PySwigPacked_str in example_wrap.o __SWIG_This in example_wrap.o _SWIG_Python_TypeQuery in example_wrap.o _swig_varlink_repr in example_wrap.o _swig_varlink_str in example_wrap.o _swig_varlink_str in example_wrap.o _swig_varlink_str in example_wrap.o _swig_varlink_str in example_wrap.o "_PyBool_FromLong", referenced from: _PySwigObject_own in example_wrap.o "_PyString_AsString", referenced from: _SWIG_Python_AddErrorMsg in example_wrap.o _PySwigObject_repr in example_wrap.o _PySwigObject_print in example_wrap.o _SWIG_Python_AddErrMesg in example_wrap.o _SWIG_Python_AddErrMesg in example_wrap.o _SWIG_Python_TypeError in example_wrap.o _swig_varlink_print in example_wrap.o "_PyObject_IsTrue", referenced from: _PySwigObject_own in example_wrap.o "_PyList_Type", referenced from: _PyList_Type$non_lazy_ptr in example_wrap.o "_PyInt_AsLong", referenced from: _SWIG_AsVal_double in example_wrap.o _SWIG_AsVal_long in example_wrap.o "_PyErr_SetString", referenced from: _SWIG_Python_SetErrorMsg in example_wrap.o _SWIG_Python_UnpackTuple in example_wrap.o _swig_varlink_getattr in example_wrap.o _swig_varlink_setattr in example_wrap.o "_malloc", referenced from: _PySwigClientData_New in example_wrap.o _PySwigPacked_New in example_wrap.o _SWIG_Python_addvarlink in example_wrap.o _SWIG_Python_addvarlink in example_wrap.o _SWIG_Python_FixMethods in example_wrap.o "_PyList_New", referenced from: _SWIG_Python_AppendOutput in example_wrap.o "_PyErr_SetObject", referenced from: _SWIG_Python_SetErrorObj in example_wrap.o "_strncmp", referenced from: _PySwigPacked_compare in example_wrap.o _SWIG_Python_FixMethods in example_wrap.o "_PyObject_Malloc", referenced from: _PySwigObject_New in example_wrap.o _PySwigPacked_New in example_wrap.o _SWIG_Python_newvarlink in example_wrap.o "_PyExc_RuntimeError", referenced from: _PyExc_RuntimeError$non_lazy_ptr in example_wrap.o "_PyCFunction_Type", referenced from: _PyCFunction_Type$non_lazy_ptr in example_wrap.o "__Py_NoneStruct", referenced from: __Py_NoneStruct$non_lazy_ptr in example_wrap.o "__PyWeak
Re: web development in python 2.6 and 3.0
so python 2.6, mysql 5.0, apache 2.2, mod_wsgi, MySQL-python-1.2.2.win32-py2.6 and Django should be sufficient for my requirement. The INTERNET now has a personality. YOURS! See your Yahoo! Homepage. http://in.yahoo.com/-- http://mail.python.org/mailman/listinfo/python-list
Re: I need your opinion...
Thanks for the answer, it's perfect for my purposes. See you in other thread!!! On Mon, Dec 21, 2009 at 6:47 PM, Stephen Hansen wrote: > On Mon, Dec 21, 2009 at 8:23 AM, logan tag wrote: > >> It should be interesting to add new funcionality to "copytree" function >> into a "shutil.py" module?, I mean...I have developed a very silly function >> "copytree" with a different fourth argument. I have modified the "ignore" >> parameter to "target" parameter; this new one is used to copy the files wich >> matched with the given pattern. >> Basically, the opposite of the current "copytree". >> >> Maybe were a stupid idea but I throw it anyway. >> >> Thanks in advance. >> > > I don't understand what you're actually asking. Are you asking if its > possible to 'add' new functionality into shutil yourself/manually? If so, > yes, you can just 'shutil.mynewfunction = myfunction'. But doing so is > highly discouraged, it's best to simply put this function into your own > module and import that module when needed. > > Or are you asking if such a function would be useful as an addition to the > shutil in the standard library? If so, I'd say no: every "ignore" option can > trivially be turned into a "target" by simply inverting the test and > vice-versa. There's no reason to expand the stdlib's API and make people > choose between two functions which do the same thing in opposite directions. > > Meaning, an argument which defines "ignore=" can serve the purpose of > "target=" by simply choosing to ignore everything which doesn't match what > you want to target. > > Or you might be asking something else entirely, in which case I'm sorry, > I'm not sure what it is :) > > HTH, > > --S > -- http://mail.python.org/mailman/listinfo/python-list
Re: web development in python 2.6 and 3.0
On Mon, Dec 21, 2009 at 10:34 AM, Simon Moses wrote: > > to code a web page which connects to a database and displays some rows, what > minimum software and libraries i should install? > > python 2.6, mysql 5.0, apache 2.2 and Django? thats enough? Depending on your requirements, you might not need mysql at all; Python comes with SQLite which is actually quite often more then sufficient for smaller sites. Its very fast and handles moderate concurrency quite well. Personally, I prefer to set up my web-apps with Apache + mod_wsgi, on which you can use any WSGI-compliant framework, which includes Django. http://code.google.com/p/modwsgi/wiki/IntegrationWithDjango --S -- http://mail.python.org/mailman/listinfo/python-list
Re: web development in python 2.6 and 3.0
to code a web page which connects to a database and displays some rows, what minimum software and libraries i should install? python 2.6, mysql 5.0, apache 2.2 and Django? thats enough? From: Stephen Hansen To: Simon Moses Cc: python-list@python.org Sent: Mon, 21 December, 2009 1:37:38 PM Subject: Re: web development in python 2.6 and 3.0 On Mon, Dec 21, 2009 at 9:22 AM, Simon Moses wrote: > >hi, > >i am new to python but have programming experience in few other languages. >i am trying to start with python 2.6 or 3.0. my requirement is accessing >database (mysql and/or postgresql) and web development. > >what all i should install for my requirement? >to connect to database (mysql and/or postgresql) >for web development 3.0 is a bit hard right now as there are a lot of libraries that have not yet been ported which may be required for certain frameworks, but this question is a bit hard on its own to answer... because you have a lot of choices :) For 2.6, what's your requirements? What's "web development" for you, ie what kind of development on the web are you talking about doing? If you're looking to do a database-driven web app, I've seen both Django and web2py in use and both have active communities and seem to be quite mature and interesting. But there's a lot of other options. Personally, I'm using Pylons and am very happy with it-- its a bit more low-level but that makes it better for me because I'm integrating it into an existing non-web based system. Then there's TurboGears which is built on top of Pylons in its 2.0 version, but a bit more focused on the end goal of providing a complete solution instead of a complete set of tools for you to make a solution out of. (That might be woefully mischaracterizing their perspectives on my part, if so I apologize!) Depending on what you need to do, there's for sure a framework for you to make life easier out there. At the moment, Python seems to have a million solutions to this problem and all seem quite interesting in their own regard. Then again, you could go retro and skip the framework and just use what's in the standard library and make CGI scripts... but doing it the cave-man way will make you seem less cool :) --S The INTERNET now has a personality. YOURS! See your Yahoo! Homepage. http://in.yahoo.com/-- http://mail.python.org/mailman/listinfo/python-list
Re: (unknown)
brc.hu> writes: > > petro, I think you need to use e-mail, not IMP Gil -- http://mail.python.org/mailman/listinfo/python-list
Python 3.1.1 installer botches upgrade when installation is not on C drive.
I just installed "python3.1.1.msi" on a system that had "python3.1.msi" installed in "D:/python31". The installer found the old installation in "D:/python31", partially trashed it, and then installed the new version in "C:/python31". I uninstalled the failed install, and reinstalled. On a new install, the installer prompts for the destination dir, and that works. Upgrade installs, though, are botched. John Nagle -- http://mail.python.org/mailman/listinfo/python-list
Re: How to validate the __init__ parameters
* Denis Doria: I thought in something like: class A: def __init__(self, foo = None, bar = None): set_foo(foo) self._bar = bar def set_foo(self, foo): if len(foo) > 5: raise _foo = foo foo = property(setter = set_foo) But looks too much like java Yeah. If member _foo has this constraint regardless then it's logically part of that member's type, so make it a type: class _Foo: def __init__( self, seq ): if seq is None: self.items = [] elif len( seq ) > 5: raise else: self.items = seq class A: # Your example def __init__( self, foo = None, Bar = None ): self._foo = _Foo( foo ) self._bar = bar def set_foo( self, foo ): self._foo = _Foo( foo ) foo = property( setter = set_foo ) Cheers & hth., - Alf -- http://mail.python.org/mailman/listinfo/python-list
Re: Opening File Object
On Mon, Dec 21, 2009 at 11:48 AM, Ray Holt wrote:
> I use the following code:
> fileobject = open("e:\\Ray Holts Documents\\Word Documents\\1850 Warren MS
> Jenkins", 'y')
> line = fileobject.readline()
>
> I get the following error message:Traceback (most recent call last):
> File "C:/Python26/Reading_and_Writing_Files", line 5, in
> fileobject = open("E:\\Ray Holts Documents\Word Documents\\1850 Warren
> MS Jenkins", 'r')
> IOError: [Errno 2] No such file or directory: 'E:\\Ray Holts Documents\\Word
> Documents\\1850 Warren MS Jenkins'
> I know the file exists because I opened it in MS Word. Can someone help me?
> Thanks, Ray Holt
Files usually have an extension (like .txt or .doc) but Microsoft
feels that those are too complicated so they try to hide them from
you. It's probably "1850 Warren MS Jenkins.doc" if you're opening it
with word which provides you with another problem- when you're
programming, there's no such thing as a Word document, just a
collection of 1s and 0s which will be complete nonsense if you don't
understand how Word does its formatting. Make sure it's saved as plain
text (.txt) if you're trying to open it programatically.
> --
> http://mail.python.org/mailman/listinfo/python-list
>
>
--
http://mail.python.org/mailman/listinfo/python-list
Re: How to validate the __init__ parameters
Denis Doria wrote:
Hi;
I'm checking the best way to validate attributes inside a class. Of
course I can use property to check it, but I really want to do it
inside the __init__:
class A:
def __init__(self, foo, bar):
self.foo = foo #check if foo is correct
self.bar = bar
All examples that I saw with property didn't show a way to do it in
the __init__. Just to clarify, I don't want to check if the parameter
is an int, or something like that, I want to know if the parameter do
not use more than X chars; and want to do it when I'm 'creating' the
instance; not after the creation:
a = A('foo', 'bar')
not
class A:
def __init__(self, foo = None, bar = None):
self._foo = foo
self._bar = bar
def set_foo(self, foo):
if len(foo) > 5:
raise
_foo = foo
foo = property(setter = set_foo)
a = A()
a.foo = 'foo'
I thought in something like:
class A:
def __init__(self, foo = None, bar = None):
set_foo(foo)
self._bar = bar
def set_foo(self, foo):
if len(foo) > 5:
raise
_foo = foo
foo = property(setter = set_foo)
But looks too much like java
One possible way, straight and simple
class A:
def __init__(self, foo = None, bar = None):
if len(foo) > 5:
raise ValueError('foo cannot exceed 5 characters')
self._foo = foo
self._bar = bar
JM
--
http://mail.python.org/mailman/listinfo/python-list
Re: difflib get_close_matches improvement?
Neal Becker wrote:
> difflib.get_close_matches looks useful. But, I don't see where it defines
> 'close'. Besides that, wouldn't it be much more useful if one could
> supply their own distance metric?
If you have a distance function you can find the N best matches with
>>> from heapq import nsmallest
>>> from functools import partial
>>> from Levenshtein import distance
>>> possibilities = ["ape", "apple", "peach", "puppy"]
>>> nsmallest(3, possibilities, key=partial(distance, "appel"))
['ape', 'apple', 'puppy']
With a cutoff it gets a bit messier...
>>> pairs = ((distance("appel", v), v) for v in possibilities)
>>> pairs = ((score, v) for score, v in pairs if score <= 2)
>>> [v for score, v in nsmallest(3, pairs)]
['ape', 'apple']
so you would want to wrap it in a function, but if you have a look into
difflib.get_close_matches()...
def get_close_matches(word, possibilities, n=3, cutoff=0.6):
if not n > 0:
raise ValueError("n must be > 0: %r" % (n,))
if not 0.0 <= cutoff <= 1.0:
raise ValueError("cutoff must be in [0.0, 1.0]: %r" % (cutoff,))
result = []
s = SequenceMatcher()
s.set_seq2(word)
for x in possibilities:
s.set_seq1(x)
if s.real_quick_ratio() >= cutoff and \
s.quick_ratio() >= cutoff and \
s.ratio() >= cutoff:
result.append((s.ratio(), x))
# Move the best scorers to head of list
result = heapq.nlargest(n, result)
# Strip scores for the best n matches
return [x for score, x in result]
there is a lot of stuff that only makes sense if you use a SequenceMatcher
to calculate the similarity. For a generalized version you will probably
have to throw out the range check for the cuttof and the optimizations.
I don't think it's worthwile.
Peter
--
http://mail.python.org/mailman/listinfo/python-list
Re: How to validate the __init__ parameters
On Mon, Dec 21, 2009 at 9:41 AM, Denis Doria wrote:
> All examples that I saw with property didn't show a way to do it in
> the __init__. Just to clarify, I don't want to check if the parameter
> is an int, or something like that, I want to know if the parameter do
> not use more than X chars; and want to do it when I'm 'creating' the
> instance; not after the creation:
>
> a = A('foo', 'bar')
>
> not
>
> class A:
>def __init__(self, foo = None, bar = None):
>self._foo = foo
>self._bar = bar
>def set_foo(self, foo):
>if len(foo) > 5:
> raise
>_foo = foo
>foo = property(setter = set_foo)
>
> a = A()
> a.foo = 'foo'
>
>
If I understand your requirements correctly-- you should just use
self.foo = foo
in your __init__, as opposed to the backdoor
self._foo = foo
Properties are probably the best way to get what you want, and if you want
to have the verification done, just don't bypass properties by assigning
into the private variable. Just because its fair-game for methods of a
class(and especially a classes initializer) to assign to the
"pseudo-private" member variables, doesn't mean it /has/ to or even /should/
:)
--S
--
http://mail.python.org/mailman/listinfo/python-list
Re: I need your opinion...
On Mon, Dec 21, 2009 at 8:23 AM, logan tag wrote: > It should be interesting to add new funcionality to "copytree" function > into a "shutil.py" module?, I mean...I have developed a very silly function > "copytree" with a different fourth argument. I have modified the "ignore" > parameter to "target" parameter; this new one is used to copy the files wich > matched with the given pattern. > Basically, the opposite of the current "copytree". > > Maybe were a stupid idea but I throw it anyway. > > Thanks in advance. > I don't understand what you're actually asking. Are you asking if its possible to 'add' new functionality into shutil yourself/manually? If so, yes, you can just 'shutil.mynewfunction = myfunction'. But doing so is highly discouraged, it's best to simply put this function into your own module and import that module when needed. Or are you asking if such a function would be useful as an addition to the shutil in the standard library? If so, I'd say no: every "ignore" option can trivially be turned into a "target" by simply inverting the test and vice-versa. There's no reason to expand the stdlib's API and make people choose between two functions which do the same thing in opposite directions. Meaning, an argument which defines "ignore=" can serve the purpose of "target=" by simply choosing to ignore everything which doesn't match what you want to target. Or you might be asking something else entirely, in which case I'm sorry, I'm not sure what it is :) HTH, --S -- http://mail.python.org/mailman/listinfo/python-list
Re: Please Help Publicize PyCon
There is huge difference between what Steve is asking and spam. Spam is "Unsolicited e-mail, often of a commercial nature, sent indiscriminately to multiple mailing lists, individuals, or newsgroups". Steve is asking us help him to identify communities that we may be part of and that we believe may be interested in the PyCon conference and inform them. Not every communication on the internet is spam. Massimo On Dec 21, 11:31 am, John Nagle wrote: > Steve Holden, Chairman, PSF wrote:> Hi,everyone. > > > This year I hope all readers of this list will assist me in crass > > commercial promotion of next year's PyCon. > ... > > One particularly effective way for you prodigious email producers to > > assist is to something to your signature (as you will see I have done). > > ... > > This guy wants people to spam for him to promote his $300 conference. > > Don't support spammers. Boycott PyCon. > > John Nagle -- http://mail.python.org/mailman/listinfo/python-list
How to validate the __init__ parameters
Hi;
I'm checking the best way to validate attributes inside a class. Of
course I can use property to check it, but I really want to do it
inside the __init__:
class A:
def __init__(self, foo, bar):
self.foo = foo #check if foo is correct
self.bar = bar
All examples that I saw with property didn't show a way to do it in
the __init__. Just to clarify, I don't want to check if the parameter
is an int, or something like that, I want to know if the parameter do
not use more than X chars; and want to do it when I'm 'creating' the
instance; not after the creation:
a = A('foo', 'bar')
not
class A:
def __init__(self, foo = None, bar = None):
self._foo = foo
self._bar = bar
def set_foo(self, foo):
if len(foo) > 5:
raise
_foo = foo
foo = property(setter = set_foo)
a = A()
a.foo = 'foo'
I thought in something like:
class A:
def __init__(self, foo = None, bar = None):
set_foo(foo)
self._bar = bar
def set_foo(self, foo):
if len(foo) > 5:
raise
_foo = foo
foo = property(setter = set_foo)
But looks too much like java
--
http://mail.python.org/mailman/listinfo/python-list
Re: For...in statement and generators
En Mon, 21 Dec 2009 11:39:46 -0300, Lucas Prado Melo escribió: Is there a way to send() information back to a generator while using the for...in statement? No. You have to write the iteration as a while loop. -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: web development in python 2.6 and 3.0
On Mon, Dec 21, 2009 at 9:22 AM, Simon Moses wrote: > hi, > > i am new to python but have programming experience in few other languages. > i am trying to start with python 2.6 or 3.0. my requirement is accessing > database (mysql and/or postgresql) and web development. > > what all i should install for my requirement? > to connect to database (mysql and/or postgresql) > for web development > 3.0 is a bit hard right now as there are a lot of libraries that have not yet been ported which may be required for certain frameworks, but this question is a bit hard on its own to answer... because you have a lot of choices :) For 2.6, what's your requirements? What's "web development" for you, ie what kind of development on the web are you talking about doing? If you're looking to do a database-driven web app, I've seen both Django and web2py in use and both have active communities and seem to be quite mature and interesting. But there's a lot of other options. Personally, I'm using Pylons and am very happy with it-- its a bit more low-level but that makes it better for me because I'm integrating it into an existing non-web based system. Then there's TurboGears which is built on top of Pylons in its 2.0 version, but a bit more focused on the end goal of providing a complete solution instead of a complete set of tools for you to make a solution out of. (That might be woefully mischaracterizing their perspectives on my part, if so I apologize!) Depending on what you need to do, there's for sure a framework for you to make life easier out there. At the moment, Python seems to have a million solutions to this problem and all seem quite interesting in their own regard. Then again, you could go retro and skip the framework and just use what's in the standard library and make CGI scripts... but doing it the cave-man way will make you seem less cool :) --S -- http://mail.python.org/mailman/listinfo/python-list
web development in python 2.6 and 3.0
hi, i am new to python but have programming experience in few other languages. i am trying to start with python 2.6 or 3.0. my requirement is accessing database (mysql and/or postgresql) and web development. what all i should install for my requirement? to connect to database (mysql and/or postgresql) for web development thanks and regards, Simon Moses. The INTERNET now has a personality. YOURS! See your Yahoo! Homepage. http://in.yahoo.com/-- http://mail.python.org/mailman/listinfo/python-list
Re: Please Help Publicize PyCon
Steve Holden, Chairman, PSF wrote: Hi,everyone. This year I hope all readers of this list will assist me in crass commercial promotion of next year's PyCon. ... One particularly effective way for you prodigious email producers to assist is to something to your signature (as you will see I have done). ... This guy wants people to spam for him to promote his $300 conference. Don't support spammers. Boycott PyCon. John Nagle -- http://mail.python.org/mailman/listinfo/python-list
py2exe "for loop" hangs in compiled program
Dear reader,
the application is an interface to a sqlite database and stores image
metadata (such as year, event, photographer, people on image etc.). i use
pyqt4 for the interface and developed this application on a linux platform
(python 2.5.4). friends of mine liked what i have done an want it for their
windows computers. so i setup a test system (win XP and python 2.6.?).
copying the code to this system and starting it: works as intended. however
they complain python whats this, this is sooo complicated etc. so i took
refuge in using py2exe, planing to give them a zip compressed archive ...
testing this option i found out that on the surface all looks nice (GUI and
functions etc) however:
extending to "larger" datasets (>~50 images) some of the for loops stop
after some time.
e.g:
def update_allImages(self):
self.set_statusbar(unicode("Daten werden für alle angezeigten Bilder
eingetragen"))
for row in range(self.liwi.count()):
item=self.liwi.item(row)
md5=item.toolTip()#.split("<")[0]
md5=unicode(md5.split("<")[0])
self.md5TOimdata[md5].addyear(self.ui.year_comboBox.currentText())
self.md5TOimdata[md5].addEvent(self.ui.event_comboBox.currentText())
self.md5TOimdata[md5].addauth(self.ui.Author_cb.currentText())
comment=self.ui.CommentInput_text.toPlainText()
if comment:
comment.append("; ")
self.md5TOimdata[md5].addcomment(comment)
for i in range(self.ui.people_listWidget.count()):
pitem=self.ui.people_listWidget.item(i)
name=pitem.text()
self.md5TOimdata[md5].addperson(name)
item.setToolTip(self.md5TOimdata[md5].generateToolTip())
self.liwi.setCurrentItem(item)
self.md5TOimdata[md5].update_DB()
self.set_statusbar(unicode("Alles eingetragen: Bereit"))
sorry for the german strings in the statusbar (to be changed in future
versions)
in the third line the problematic "for" starts. at about item 42 or 43 the
statusbar stays on what is in line 2 and nothing more happens. so the first
42 items get updated the rest not. well i can restart this process but
success is limited only view more items get updated. note that this code
works fine in linux and in windows (python commandline) but hangs as
described after py2exe.
a second example is when i try to load many images (~130) again here is a
for loop iterating over filenames. the pure python versions work as they
should but not the py2exe.
def ImLoad(self):
""" This method is called by clicking on the "load images" button.
It loads the
selected images from the source and copies them to the db
filesystem.
Of course it is checked whether the image is allready in the db
(no insertion
happens) or if its is even loaded (not going to be loaded twice)
"""
fileNames = QtGui.QFileDialog.getOpenFileNames(self,
"Bild(er) laden", "", "Bild Dateien (*.png *.jpg *.bmp *.tif)")
for fileName in fileNames:
#work is done
therefore i think its in the" for" loops.
thanks in advance. just ask if you need more info. kind regards Jo
--
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Re: Opening File Object
Ray Holt wrote:
I use the following code:
fileobject = open("e:\\Ray Holts Documents\\Word Documents\\1850 Warren
MS Jenkins", 'y')
line = fileobject.readline()
I get the following error message:Traceback (most recent call last):
File "C:/Python26/Reading_and_Writing_Files", line 5, in
fileobject = open("E:\\Ray Holts Documents\Word Documents\\1850
Warren MS Jenkins", 'r')
IOError: [Errno 2] No such file or directory: 'E:\\Ray Holts
Documents\\Word Documents\\1850 Warren MS Jenkins'
I know the file exists because I opened it in MS Word. Can someone help
me?
Look for the file using Windows Explorer. I expect that the filename has
an extension, which you're omitting.
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Ch 3 of my writings, first few sections posted
Tentatively titled "Foundations". Also, these first 2/3 sections may be moved to some later point, i.e. even the structure is tentative, but I'd value comments! http://tinyurl.com/programmingbookP3> Table of contents: 3 Foundations 1 3.1 Some necessary math notation & terminology. 2 3.1.1 The vocabulary and notation of basic arithmetic, including Σ and Π. 2 3.1.2 Quadratic and exponential time & memory (also introducing timeit). 5 -EOT_ 9 Cheers, - Alf PS: Hm, Open Office's PDF generation does funny things with Greek sigmas inside formulas! I don't mind so much that it makes table divider lines very fat and bold and that it can't handle certain figures (which I have to paste in manually as bitmaps), but really it should be able to handle simple text. Grr. -- http://mail.python.org/mailman/listinfo/python-list
Opening File Object
I use the following code:
fileobject = open("e:\\Ray Holts Documents\\Word Documents\\1850 Warren MS
Jenkins", 'y')
line = fileobject.readline()
I get the following error message:Traceback (most recent call last):
File "C:/Python26/Reading_and_Writing_Files", line 5, in
fileobject = open("E:\\Ray Holts Documents\Word Documents\\1850 Warren
MS Jenkins", 'r')
IOError: [Errno 2] No such file or directory: 'E:\\Ray Holts Documents\\Word
Documents\\1850 Warren MS Jenkins'
I know the file exists because I opened it in MS Word. Can someone help me?
Thanks, Ray Holt
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Re: numpy performance and random numbers
On 2009-12-19 09:14 AM, Carl Johan Rehn wrote: On Dec 19, 2:49 pm, sturlamolden wrote: On 19 Des, 11:05, Carl Johan Rehn wrote: I plan to port a Monte Carlo engine from Matlab to Python. However, when I timed randn(N1, N2) in Python and compared it with Matlab's randn, Matlab came out as a clear winner with a speedup of 3-4 times. This was truly disappointing. I ran tthis test on a Win32 machine and without the Atlas library. This is due to the algorithm. Matlab is using Marsaglia's ziggurat method. Is is the fastest there is for normal and gamma random variates. NumPy uses the Mersenne Twister to produce uniform random deviates, and then applies trancendental functions to transform to the normal distribution. Marsaglia's C code for ziggurat is freely available, so you can compile it yourself and call from ctypes, Cython or f2py. The PRNG does not use BLAS/ATLAS. Thank you, this was very informative. I know about the Mersenne Twister, but had no idea about Marsaglia's ziggurat method. I will definitely try f2py or cython. It's worth noting that the ziggurat method can be implemented incorrectly, and requires some testing before I will accept such in numpy. That's why we don't use the ziggurat method currently. C.f. http://www.doornik.com/research/ziggurat.pdf Requests for the ziggurat method come up occasionally on the numpy list, but so far no one has shown code or test results. Charles Harris and Bruce Carneal seem to have gotten closest. You can search numpy-discussion's archive for their email addresses and previous threads. Additionally, you should ask future numpy questions on the numpy-discussion mailing list. http://www.scipy.org/Mailing_Lists -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: Object Relational Mappers are evil (a meditation)
Lie Ryan writes: > On 12/17/2009 3:17 PM, J Kenneth King wrote: >> A language is a thing. It may have syntax and semantics that bias it >> towards the conventions and philosophies of its designers. But in the >> end, a language by itself would have a hard time convincing a human >> being to adopt bad practises. > > Perhaps someone should make a research whether if you teach a language > to kids, where one group is taught the language filtered from "bad > words" and another group is taught all the languages' "bad words" on > purpose. Will one group have more behavioral problems compared to the > other? I would be curious to know, but the test is likely impossible without trespassing on ethical boundaries. ;) I would hypothesize that you would not find an increase in behavioural problems. a) Without cultural context "bad words" have little meaning b) Behavioural issues can be attributed to several factors such as physiology, health, environment, etc. c) This has nothing to do with programming languages. A programmer that lacks critical thinking is a bad programmer. The language they use has no bearing on such human facilities. -- http://mail.python.org/mailman/listinfo/python-list
how to register with pypi
Pythonistas: I'm stuck on the "PGP Key ID". When I whip out my trusty Ubuntu and run pgp -kg, I get a 16-digit "DSA / EIGamal" key. When I enter it into http://pypi.python.org/pypi?%3Aaction=register_form , I get a helpful "PGP Key ID is invalid". Should I try a key of some other algorithm? -- Phlip http://c2.com/cgi/wiki?ZeekLand -- http://mail.python.org/mailman/listinfo/python-list
I need your opinion...
It should be interesting to add new funcionality to "copytree" function into a "shutil.py" module?, I mean...I have developed a very silly function "copytree" with a different fourth argument. I have modified the "ignore" parameter to "target" parameter; this new one is used to copy the files wich matched with the given pattern. Basically, the opposite of the current "copytree". Maybe were a stupid idea but I throw it anyway. Thanks in advance. Logan!! PS: def copytree(src, dst, symlinks=False, target=None) def target_patterns(*patterns) -- http://mail.python.org/mailman/listinfo/python-list
Re: For...in statement and generators
"Lucas Prado Melo" wrote in message news:9f4be2240912210639g58da0549jb0c81450947ef...@mail.gmail.com... Is there a way to send() information back to a generator while using the for...in statement? Thanks in advance. Yes, see "send(), (generator method)" or "yield expressions" in the help. -Mark -- http://mail.python.org/mailman/listinfo/python-list
Re: Sending ^C
On 2009-12-21, Rick wrote: > I am to write script which is to read data from log file which > resides on remote host. It's a simple text file but grows to > couple of MBytes. I want to do ssh connection to remote, and > run 'tail -f _some_file_' command to read only new coming data > and process them in the loop. The problem is, I don't know how > to deal with it when log file rotates and change name. I need > then to break running 'tail -f _some_file_' and excecute 'tail > -f _other_file'. Can you give me hints how to do this? import os,signal os.kill(pid,signal.SIGINT) -- Grant Edwards grante Yow! ! Now I understand at advanced MICROBIOLOGY and visi.comth' new TAX REFORM laws!! -- http://mail.python.org/mailman/listinfo/python-list
