Re: safest way to kill a thread
I think only those threads which invoked with setDaemon() method will exit, and others will not, as the main program exit. [EMAIL PROTECTED] wrote: limodou wrote: Using Thread's method setDaemon() before you call the start() method. Just like : t.setDaemon(True) t.start() thank for fast reply. from python.org doc, said that setDaemon() function as "The entire Python program exits when no active non-daemon threads are left." is it mean that when the main program exit (normally/abnormally), all threads created will also exit? Thank again. -- I love python! My Blog: http://www.donews.net/limodou -- http://mail.python.org/mailman/listinfo/python-list
Re: Solutions for data storage?
Leif K-Brooks <[EMAIL PROTECTED]> schreef: > > I've looked at SQLObject, and it's very nice, but it doesn't > provide certain features I really want, like the ability to store > lists of strings or integers directly in the database (using commas > in a varchar column or something). What exactly in SQLObject prevents you from doing this? You may have to pack/unpack the list into a comma separated string yourself, but surely the 2 line code function that requires can't be the problem. And SQLObject's support for properties makes this very clean. See: http://www.sqlobject.org/docs/SQLObject.html#adding-magic-attributes-properties Or am I missing something here? Regards, Jan -- http://mail.python.org/mailman/listinfo/python-list
Re: safest way to kill a thread
limodou wrote: >Using Thread's method setDaemon() before you call the start() method. >Just like : >t.setDaemon(True) >t.start() thank for fast reply. from python.org doc, said that setDaemon() function as "The entire Python program exits when no active non-daemon threads are left." is it mean that when the main program exit (normally/abnormally), all threads created will also exit? Thank again. -- http://mail.python.org/mailman/listinfo/python-list
Solutions for data storage?
I'm writing a relatively simple multi-user public Web application with Python. It's a rewrite of a similar application which used PHP+MySQL (not particularly clean code, either). My opinions on various Web frameworks tends to vary with the phase of the moon, but currently, I'm planning to use Quixote. Needless to say, my application will need some kind of persistent data storage. The previous PHP+MySQL application uses around 1.1GB of storage, so something like PyPerSyst where everything is kept in memory is out. I've looked at SQLObject, and it's very nice, but it doesn't provide certain features I really want, like the ability to store lists of strings or integers directly in the database (using commas in a varchar column or something). ZODB is very nice, but IndexedCatalog doesn't seem to provide any automatic mechanisms for things like ensuring attribute uniqueness (for e.g. usernames). I suppose I could implement manual checking in every class that needs it, but it really seems like very error-prone code to be implementing at the application level. My ideal solution would be an object database (or object-relational mapper, I guess) which provided total transparency in all but a few places, built-in indexing, built-in features for handling schema changes, the ability to create attributes which are required to be unique among other instances, and built-in querying with pretty syntax. Atop seems to come pretty close, but since it's meant to be used in the asynchronous Twisted environment, it doesn't provide any thread safety. So basically, I'm wondering if there are any Python data storage solutions I haven't noticed that come a bit closer to what I'm looking for. I could live without built-in schema evolution; the querying is really the most important feature I want. -- http://mail.python.org/mailman/listinfo/python-list
Re: File objects? - under the hood question
On Tue, 18 Jan 2005 22:53:10 -0800, Eric Pederson <[EMAIL PROTECTED]> wrote:
>
> I didn't come across any illuminating discussion via Google, thus my question
> here (though it may be a neophyte question.) I am interested in the workings
> under the hood of Python's access of "files".
>
> What is actually happening at the various stages when I create a file object
> and "read" it?
>
> (1)>>> f = file("C:/GuidosParrot.txt","r")
You've just opened a file for reading. You haven't read any data, but
at this point if the file wasn't there, the OS would have throw you an
error.
> (2)>>> hesjustsleeping = f.read()
The entire file is read directly into a single python str.
Regards,
Stephen Thorne.
--
http://mail.python.org/mailman/listinfo/python-list
Re: generator expressions: performance anomaly?
On Tue, 18 Jan 2005 23:09:57 -0700, Steven Bethard
<[EMAIL PROTECTED]> wrote:
> @with_consts(i=1, deftime=time.ctime())
> def foo(x, y=123, *args, **kw):
> return x*y, kw.get('which_time')=='now' and time.ctime() or deftime
>
> Then you don't have to mix parameter declarations with locals definitions.
>
> [1] I have no idea how implementable such a decorator would be. I'd
> just like to see function constants declared separate from arguments
> since they mean such different things.
(untested)
def with_constant(**constants_kwargs):
def decorator(f)
def closure(*arg, **kwargs):
kwargs.update(constants_kwargs)
return f(*arg, **kwargs)
return closure
return decorator
Regards,
Stephen Thorne
--
http://mail.python.org/mailman/listinfo/python-list
File objects? - under the hood question
I didn't come across any illuminating discussion via Google, thus my question
here (though it may be a neophyte question.) I am interested in the workings
under the hood of Python's access of "files".
What is actually happening at the various stages when I create a file object
and "read" it?
(1)>>> f = file("C:/GuidosParrot.txt","r")
(2)>>> hesjustsleeping = f.read()
At (1) have I loaded the file from hard drive into RAM when I create the file
object? What does this object know and how did it find it out?
At (2) am I loading the file contents into RAM, or just assigning what is
already in RAM to a variable?
Where is the work split between the OS and Python? I assume the OS is
responsible for "presenting" the file to Python, so perhaps the OS assembles
this file from the blocks on disk and loads it into RAM at the time the file
object is created? Or would the OS simply have pointers that can assemble the
file, and pass those pointers to Python?
Perhaps I've answered my question and the under-the-hood mechanics are handled
on the OS side, and Python is just making requests of the OS...
My brain-teaser: What I'd like to do is read the last ~2K of a large number of
large files on arbitrary servers across the net, without having to read each
file from the beginning (which would be slow and resource inefficient)...
Eric Pederson
http://www.songzilla.blogspot.com
:::
domainNot="@something.com"
domainIs=domainNot.replace("s","z")
ePrefix="".join([chr(ord(x)+1) for x in "do"])
mailMeAt=ePrefix+domainIs
:
--
http://mail.python.org/mailman/listinfo/python-list
Re: makepy crashing
Looks like the makepy step creates the generated file successfully, but python is choking with an assertion failure on lines longer than 512 when it tries to import it. This is the line it was processing when it died: def GetSpellingSuggestions(self, Word=defaultNamedNotOptArg, CustomDictionary=defaultNamedOptArg, IgnoreUppercase=defaultNamedOptArg, MainDictionary=defaultNamedOptArg, SuggestionMode=defaultNamedOptArg, CustomDictionary2=defaultNamedOptArg, CustomDictionary3=defaultNamedOptArg, CustomDictionary4=defaultNamedOptArg, CustomDictionary5=defaultNamedOptArg, CustomDictionary6=defaultNamedOptArg, CustomDictionary7=defaultNamedOptArg, CustomDictionary8=defaultNamedOptArg, CustomDictionary9=defaultNamedOptArg, CustomDictionary10=defaultNamedOptArg): You might be able to do a workaround by hacking genpy.py and replacing the defaultArg names with something shorter. ...Nope, there are a few other lines that exceed 512. I think it's a problem with the encoding. If you remove the mbcs tag (# -*- coding: mbcs -*-) from the top of the generated file, the import succeeds. Roger <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Has anyone sucessfully run makepy and Microsoft Word Object Library > (9.0)? Mine crashes under XP Pro and Python 2.4. > > It only seems to be word that has the problem, though. > > I get a dialog that says that pythonwin.exe has crashed: > AppName: pythonwin.exe AppVer: 0.0.0.0 ModName: ntdll.dll > ModVer: 5.1.2600.1217 Offset: 96f9 > == Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News== http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- -- http://mail.python.org/mailman/listinfo/python-list
Re: generator expressions: performance anomaly?
Bengt Richter wrote:
On Tue, 18 Jan 2005 17:38:20 -0700, Steven Bethard <[EMAIL PROTECTED]> wrote:
Bengt Richter wrote:
Which make me wonder what plans there are for providing a better
mechanism than default arguments as a way of initializing local function
variables. Nested def's to create a closure with initialized values is
pretty crufty for that, IMO.
What about using a class? Associating functions with data is pretty
much what they're for...
Maybe extending the default argument space
with whatever comes after e.g. a triple star delimiter in the argument list,
but which wouldn't be counted as part of the normal arguments? E.g.,
def foo(x, y=123, *args, **kw, *** i=1, deftime=time.ctime()):
return x*y, kw.get('which_time')=='now' and time.ctime() or deftime
If what you want is to have i=1 and deftime=time.ctime() available
within foo, you could do something like (untested):
class foo(object):
def __init__(self):
self.i = 1
self.deftime = time.ctime()
def __call__(self, x, y=123, *args, **kwds):
return x*y, (kw.get('which_time') == 'now'
and time.ctime() or self.deftime)
foo = foo()
Total: 8 lines, much irrelevant cruft.
Or if you don't like 'foo = foo()', you could probably abuse the __new__
method (also untested):
class foo(object):
i = 1
deftime = time.ctime()
def __new__(cls, x, y=123, *args, **kwds):
return x*y, (kw.get('which_time') == 'now'
and time.ctime() or self.deftime)
Total: 6 lines, newbie-unfriendly abuse of __new__ ;-)
I guess my point is that if you want attribute associated with the
function, it's often easy enough to write a class instead...
vs. 2 easy lines with minimal irrelevant cruft ;-)
If you're really counting lines, you might compare with the more compact:
class foo(object):
def __init__(self):
self.i, self.deftime = 1, time.ctime()
def __call__(self):
return x*y, kw.get('which_time') == 'now' and time.ctime() or
self.deftime
foo = foo()
and
class foo(object):
i, deftime = 1, time.ctime()
def __new__(cls, x, y=123, *args, **kwds):
return x*y, kw.get('which_time') == 'now' and time.ctime() or
self.deftime
And probably what you want to compare is N lines (function only) versus
N + 2 lines (using __new__) and N + 4 lines (using __call__). If N is
more than 2 lines (which is probably true in most cases), the difference
isn't so dramatic.
Using a class also has the advantage that, assuming one already knows
how classes work (which any Python programmer who wants the kind of
scoping you're talking about should) you don't have to learn how
something new to be able to use it -- that is, *** -> bound locals that
don't contribute to arguments but are listed in the same place as arguments.
If you really want locals that don't contribute to arguments, I'd be
much happier with something like a decorator, e.g.[1]:
@with_consts(i=1, deftime=time.ctime())
def foo(x, y=123, *args, **kw):
return x*y, kw.get('which_time')=='now' and time.ctime() or deftime
Then you don't have to mix parameter declarations with locals definitions.
Steve
[1] I have no idea how implementable such a decorator would be. I'd
just like to see function constants declared separate from arguments
since they mean such different things.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Window capture using WM_PRINT and Python
Do you get any kind of traceback when you start a process that way?
There's not much info to go on.
Sys.argv parameters are passed as strings. You'll need to do an int() on
them
before you can use them as handles. Also, not all handles are portable
between processes. Your device context handle might not be valid
even if you make it an int.
hth
Roger
"arN" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Hi !
>
> I'm a Java developper and I wish to make a capture of an offscreen window
> (on WinXP). It's not possible in Java, so I use a python script and
> WM_PRINT, but it doesn't seem to work.
>
> Could someone have a look at my script and give me any advise ?
>
> TIA
>
> --
> Arnaud
> my python script : python snap.py GraphicalContext_handle image_handle
> --
> snap.py :
> "
> import win32api, win32con, sys
>
> win32api.SendMessage(sys.argv[2], win32con.WM_PAINT, sys.argv[3], 0)
> win32api.SendMessage(sys.argv[2], win32con.WM_PRINT, sys.argv[3],
> win32con.PRF_CHILDREN | win32con.PRF_CLIENT | win32con.PRF_OWNED)
> "
>
>
> snippet from Snapshot.java :
> "
> public static Image snapshot(Composite bean) {
> GC gc = new GC(bean);
> final Image image = new Image (null, bean.getBounds().width,
> bean.getBounds().height);
> String commmand = "python snap.py " + gc.handle + " " + image.handle;
>
> Runtime rt = Runtime.getRuntime();
> try {
> Process p = rt.exec(command);
> } catch (.)
>
> gc.dispose();
> return image;
> }
> "
== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==
http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000
Newsgroups
---= East/West-Coast Server Farms - Total Privacy via Encryption =---
--
http://mail.python.org/mailman/listinfo/python-list
Re: python/cgi/html bug
Dfenestr8 wrote: > Hi. > > I've written a cgi messageboard script in python, for an irc chan I happen > to frequent. > > Bear with me, it's hard for me to describe what the bug is. So I've > divided this post into two sections: HOW MY SCRIPTS WORKS, and WHAT THE > BUG IS. > ... > The problem is when someone posts a new topic, and that topic happens to > have "" double quotes, or any other strange character, some strange > glitches occur. Use cgi.escape(topic, True) to convert HTML special characters to the equivalent ampersand escape sequences. -- http://mail.python.org/mailman/listinfo/python-list
Error in Plex 1.1.4.1
Hello,
I got the following error while using Plex 1.1.4.1
D:\Python24\myfiles>python plex1.py
Traceback (most recent call last):
File "plex1.py", line 1, in ?
from Plex import *
File "D:\python24\lib\site-packages\Plex\__init__.py", line 34, in ?
from Lexicons import Lexicon, State
File "D:\python24\lib\site-packages\Plex\Lexicons.py", line 12, in ?
import DFA
File "D:\python24\lib\site-packages\Plex\DFA.py", line 9, in ?
import Machines
File "D:\python24\lib\site-packages\Plex\Machines.py", line 14, in ?
from Transitions import TransitionMap
File "D:\python24\lib\site-packages\Plex\Transitions.py", line 85
def get_epsilon(self,
SyntaxError: Invalid syntax. Assignment to None.
The corresponding source code :
#file plex1.py
from Plex import *
lexicon = Lexicon([
(Str("Python"), "my_favourite_language"),
(Str("Perl"),"the_other_language"),
(Str("rocks"), "is_excellent"),
(Str("sucks"), "is_differently_good"),
(Rep1(Any(" \t\n")), IGNORE)
])
filename = "plex1.txt"
f = open(filename, "r")
scanner = Scanner(lexicon, f, filename)
while 1:
token = scanner.read()
print token
if token[0] is None:
break
The error was removed when I used the following code in Transitions.py
def get_epsilon(self,
none = None):
"""
Return the mapping for epsilon, or None.
"""
return self.special.get('', None)
Regards,
Srijit
--
http://mail.python.org/mailman/listinfo/python-list
[perl-python] 20050119 writing modules
© # -*- coding: utf-8 -*-
© # Python
©
© # one can write functions,
© # save it in a file
© # and later on load the file
© # and use these functions.
©
© # For example, save the following line in
© # a file and name it module1.py
© # def f1(n): returns range(n)
©
© # to load the file, use import
© import mymodule
©
© # to use the function, use
© # fileName.functionName.
© print mymodule.f1(5)
©
© # the file name without the .py suffix
© # is the module's name, and is available
© # as the variable fileName.__name__
© print mymodule.__name__
©
© # for more on modules, see
© # http://python.org/doc/2.3.4/tut/node8.html
©
©
© # the perl analogue is like this:
© # save the following 3 lines in a file
© # and name it mymodule.pm
©
© # package mymodule;
© # sub f1($){(1..$_[0])}
© # 1
©
© # then, call it like the following way
© use mymodule;
© use Data::Dumper;
© print Dumper [&mymodule::f1(7)];
©
© # this is about the simplest way
© # to write a modlue in perl and
© # calling its function.
© # for an inscrutable treatment,
© # see "perldoc perlmod"
©
© Xah
© [EMAIL PROTECTED]
© http://xahlee.org/PageTwo_dir/more.html
--
http://mail.python.org/mailman/listinfo/python-list
Re: rotor replacement
"Reed L. O'Brien" <[EMAIL PROTECTED]> writes: > I see rotor was removed for 2.4 and the docs say use an AES module > provided separately... Is there a standard module that works alike or > an AES module that works alike but with better encryption? If you mean a module in the distribution, the answer is no, for political reasons. There are a number of AES modules available on the net. Most are C extension modules which means you need to compile them, and if you want to deploy them widely, you need binaries for every target platform. There's a few pure-Python AES implementations but they are verrry slow. Here's something written in Python that uses the built-in sha1 module as a crypto primitive. Its security should be better than rotor and performance is reasonable for most applications: http://www.nightsong.com/phr/crypto/p3.py -- http://mail.python.org/mailman/listinfo/python-list
Re: Has apparent 2.4b1 bug been fixed? flatten in Lib\compiler\ast.py overloads 'list' name
On Wed, 19 Jan 2005 04:55:53 GMT, [EMAIL PROTECTED] (Bengt Richter) wrote: >What am I missing? (this is from 2.4b1, so probably it has been fixed?) > I googled and found a bug report, but initial report kind of passes on it saying nested sequences will probably be tuples, so no panic (my paraphrased description). So I guess it's in the mill. So never mind. I should have googled first ;-/ > >def flatten(list): >l = [] >for elt in list: > --must be expecting list instance or other sequence >t = type(elt) >if t is tuple or t is list: > --looks like it expects to refer to the > type, not the arg >for elt2 in flatten(elt): >l.append(elt2) >else: >l.append(elt) >return l > Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
Has apparent 2.4b1 bug been fixed? flatten in Lib\compiler\ast.py overloads 'list' name
What am I missing? (this is from 2.4b1, so probably it has been fixed?) def flatten(list): l = [] for elt in list: --must be expecting list instance or other sequence t = type(elt) if t is tuple or t is list: --looks like it expects to refer to the type, not the arg for elt2 in flatten(elt): l.append(elt2) else: l.append(elt) return l Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
Re: Employablity of python programmers
Mir Nazim <[EMAIL PROTECTED]> wrote: I am in a fix what skill set I must choose to be safe as far as job openings are concerned. > 1) C/C++ and Python. > 2) Java and Python. > 3) Pure Python. As for pure employability, I'd choose option 2, but as a person that wants something more than employment from my work life, I'd like to share something with you: A while ago I decided that to be happy I had to decide what I wanted, *really* go after those things, and believe that the rewards would follow. For me Python had a big part to play in that, so I recently started looking for a new job, even though I already had one that was promising and secure. It also meant being willing to move myself and my family far from or home, friends, and other family members to take that new job. If we were willing to make big changes (and the accompanying sacrifices), we were going to make the most of it: I wouldn't accept anything but the right job, at the right company, with the right environment where they really needed *me*. I spent hours researching openings and companies and sent out many resumes with the hopes of finding that *one* job. Two weeks later, I was fortunate enough to begin talks with *two* very interested (and more importantly, interesting) companies. I've been at my new job (in a new house, in a new city) for about six weeks now. It's not perfect (nothing is), but I'm enjoying the job, like the people I work with, and the area we live in. We made the right choice. Go after what you really want, and you will too. -- Benji York Sr. Software Engineer Zope Corporation -- http://mail.python.org/mailman/listinfo/python-list
rotor replacement
I see rotor was removed for 2.4 and the docs say use an AES module provided separately... Is there a standard module that works alike or an AES module that works alike but with better encryption? cheers, reed -- http://mail.python.org/mailman/listinfo/python-list
Re: safest way to kill a thread
Using Thread's method setDaemon() before you call the start() method. Just like : t.setDaemon(True) t.start() [EMAIL PROTECTED] wrote: Dear all, in python, a thread can be created by t = threading.Thread. But i found that when the main (and the thread) program is running and user use Crtl+C/Crtl+Z to break the program abnormally, the thread is still running and needed to kill manually (by the pid). Is there had any safest way to kill/exit the thread program under python (when the thread program part is a forever loop)? Thank a lot -- I love python! My Blog: http://www.donews.net/limodou -- http://mail.python.org/mailman/listinfo/python-list
safest way to kill a thread
Dear all, in python, a thread can be created by t = threading.Thread. But i found that when the main (and the thread) program is running and user use Crtl+C/Crtl+Z to break the program abnormally, the thread is still running and needed to kill manually (by the pid). Is there had any safest way to kill/exit the thread program under python (when the thread program part is a forever loop)? Thank a lot -- http://mail.python.org/mailman/listinfo/python-list
DDE client help
Dear Python experts,
I'm facing a simple problem which however I'm having a hard time
solving. I have a DDE server with data that changes from time to time.
I need to put together a DDE client that would 'notice' updated values
on the server and append them as a new row in a text file.
1. How do I connect to the DDE server, and ask for data?
In OpenOffice.org it looks very simple:
=DDE("FPS";"TIME";"PRC")
I also have some VB code which does the same thing:
Private Sub Command1_Click()
Text1.LinkTopic = "FPS|TIME"
Text1.LinkItem = Text4.Text
Text1.LinkMode = vbLinkAutomatic
I checked the DDE client sample code from
C:\Python24\Lib\site-packages\win32\Demos\dde,
however I got stuck here:
conversation.ConnectTo("FPS","PRC")
Traceback (most recent call last):
File "", line 1, in ?
conversation.ConnectTo("FPS","PRC")
error: ConnectTo failed
2. Once I manage to connect to the DDE server, how do I append the new
data values in a text file?
Suggestions and sample code will be highly appreciated.
Thank you,
b.
__
Do you Yahoo!?
Yahoo! Mail - Helps protect you from nasty viruses.
http://promotions.yahoo.com/new_mail
--
http://mail.python.org/mailman/listinfo/python-list
Re: [perl-python] 20050118 keyed list
Tassilo v. Parseval wrote:
> Also sprach Jürgen Exner:
>
>> Xah Lee wrote:
>
>>> © %a = ('john',3, 'mary', 4, 'jane', 5, 'vicky',7);
>>> © use Data::Dumper qw(Dumper);
>>> © print Dumper \%a;
>>
>> Wow, my compliments. The very first time that using Data::Dumper
>> actually may do something useful (formats the data more nicely).
>> Still, why you are passing a reference is beyond me.
>
> How else would you use 'Dumper' on a hash?
Well, fair enough. If you do a plain
print Dumper(%a);
you do loose a lot of the nifty pretty printing that is provided by Dumper
otherwise.
jue
--
http://mail.python.org/mailman/listinfo/python-list
Re: generator expressions: performance anomaly?
Steve Holden <[EMAIL PROTECTED]> writes: > You probably already know that sensible compiled language systems have > used constant folding since time immemorial, but Python has always > eschewed it. That's what comes of being a pragmatist's language: if > such optimizations really are required the programmer is expected to > perform them. You mean the lack is deliberate? I just figured it was an artifact of the implementation and that PyPy had some reasonable chance of fixing it. -- http://mail.python.org/mailman/listinfo/python-list
Re: generator expressions: performance anomaly?
On Tue, 18 Jan 2005 17:38:20 -0700, Steven Bethard <[EMAIL PROTECTED]> wrote:
>Bengt Richter wrote:
>> Which make me wonder what plans there are for providing a better
>> mechanism than default arguments as a way of initializing local function
>> variables. Nested def's to create a closure with initialized values is
>> pretty crufty for that, IMO.
>
>What about using a class? Associating functions with data is pretty
>much what they're for...
>
>> Maybe extending the default argument space
>> with whatever comes after e.g. a triple star delimiter in the argument list,
>> but which wouldn't be counted as part of the normal arguments? E.g.,
>>
>> def foo(x, y=123, *args, **kw, *** i=1, deftime=time.ctime()):
>> return x*y, kw.get('which_time')=='now' and time.ctime() or deftime
>
>If what you want is to have i=1 and deftime=time.ctime() available
>within foo, you could do something like (untested):
>
>class foo(object):
> def __init__(self):
> self.i = 1
> self.deftime = time.ctime()
> def __call__(self, x, y=123, *args, **kwds):
> return x*y, (kw.get('which_time') == 'now'
> and time.ctime() or self.deftime)
>foo = foo()
Total: 8 lines, much irrelevant cruft.
>
>Or if you don't like 'foo = foo()', you could probably abuse the __new__
>method (also untested):
>
>class foo(object):
> i = 1
> deftime = time.ctime()
> def __new__(cls, x, y=123, *args, **kwds):
> return x*y, (kw.get('which_time') == 'now'
> and time.ctime() or self.deftime)
Total: 6 lines, newbie-unfriendly abuse of __new__ ;-)
>
>I guess my point is that if you want attribute associated with the
>function, it's often easy enough to write a class instead...
vs. 2 easy lines with minimal irrelevant cruft ;-)
Regards,
Bengt Richter
--
http://mail.python.org/mailman/listinfo/python-list
Re: Integration with java (Jpype vs. JPE)
Istvan Albert wrote: Steve Menard wrote: To asnwer your question more fully, the jpype-specific cide is only for looking up the Classes and startting/stopping the environment. For everything else, Java objects and classes are used as regular Python objects. Thanks for the response. Currently I don't need to use java but in the past when I explored such a possibility I looked at jpype and I was unable to understand from the documentation what it actually does. There is a lot of text there, but it is all concerning catching errors or other subtleties. For a new visitor the most important question is about how it works, what does it do, and how can it be applied for the given problem. > everything else, Java objects and classes are used as regular Python > objects. This is too generic. My question was a little more specific, how would I pass a python list as an argument of a java class/method or transform a java list into a python one? You don't have to answer it here, I'm just pointing out the kind of questions that I was unable to get an answer for on the jpype website. best, Istvan. I see what you mean. And I agree fully. I guess that's one more thing to put on the TODO list hehe. Thanks for the input. Steve -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem parsing namespaces with xml.dom.minidom
Hi Fredrik. Fredrik Lundh wrote: It wouldn't need to conform to the official specifications of the DOM API, but I guess I'm after some comparable functionality. [--snip--] sounds like this might be exactly what you need: http://effbot.org/zone/element-index.htm (it's also the fastest and most memory-efficient Python-only parser you can get, but I suppose that's not a problem ;-) Thanks. The original problem I was having turned out to the be reversing a couple of parameters in a method call, as Paul pointed out, and I now feel pretty silly as a result. But I'll take a look at this, too. Much appreciated. Mike. -- http://mail.python.org/mailman/listinfo/python-list
Re: file copy portability
John Machin wrote: Bob Smith wrote: Is shutil.copyfile(src,dst) the *most* portable way to copy files with Python? I'm dealing with plain text files on Windows, Linux and Mac OSX. Thanks! Portable what? Way of copying?? Do you want your files transferred (a) so that they look like native text files on the destination system, or (b) so that they are exact byte-wise copies? A 5-second squint at the source (Lib/shutil.py) indicates that it provides, reliably and portably, option b: fsrc = open(src, 'rb') fdst = open(dst, 'wb') One way of doing option (a): you would need to be running Python on the destination system, open the src file with 'rU', open the dst file with 'w'. The files are not copied from one platform to the other. The app must run on all platforms. I want to make the app as portable as possible to reduce platform specific code. -- http://mail.python.org/mailman/listinfo/python-list
Re: simultaneous multiple requests to very simple database
Thomas Bartkus wrote: When you write that "super dictionary", be sure to post code! I could use one of those myself. hmmm it looks like you have just flung down the gauntlet of "put up or quityerwhinging". I need to get the crude implementation done first but I think I can do it if I can find a good XMLRPC multithreading framework. ---eric -- http://mail.python.org/mailman/listinfo/python-list
Re: file copy portability
Bob Smith wrote: Is shutil.copyfile(src,dst) the *most* portable way to copy files with Python? I'm dealing with plain text files on Windows, Linux and Mac OSX. Thanks! Yes. regards Steve -- Steve Holden http://www.holdenweb.com/ Python Web Programming http://pydish.holdenweb.com/ Holden Web LLC +1 703 861 4237 +1 800 494 3119 -- http://mail.python.org/mailman/listinfo/python-list
Re: file copy portability
Bob Smith wrote: > Is shutil.copyfile(src,dst) the *most* portable way to copy files with > Python? I'm dealing with plain text files on Windows, Linux and Mac OSX. > > Thanks! Portable what? Way of copying?? Do you want your files transferred (a) so that they look like native text files on the destination system, or (b) so that they are exact byte-wise copies? A 5-second squint at the source (Lib/shutil.py) indicates that it provides, reliably and portably, option b: fsrc = open(src, 'rb') fdst = open(dst, 'wb') One way of doing option (a): you would need to be running Python on the destination system, open the src file with 'rU', open the dst file with 'w'. -- http://mail.python.org/mailman/listinfo/python-list
Re: file copy portability
Bob Smith wrote: Is shutil.copyfile(src,dst) the *most* portable way to copy files with Python? I'm dealing with plain text files on Windows, Linux and Mac OSX. Yes, provided you don't need any of the features provided by the other shutil.copy functions, and assuming you can live with the Caveat listed in the docs for the MacOS system... -Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: generator expressions: performance anomaly?
On Tue, 18 Jan 2005 15:29:06 +0100, "Diez B. Roggisch" <[EMAIL PROTECTED]> wrote: >> I don't see how generating byte code for a = 9; when seeing the >> expression a = 3 + 6, would be a problem for non-functional >> languages. > >Most probably. But I don't see much code of that type that it would be worth >optimizing for, either. The cost for re-evaluation such an expression >doesn't really account for any performance problems you hit - in python, of >course. >See this: > >[EMAIL PROTECTED]:/usr/lib/python2.3$ python timeit.py -c "[4*5 for i in >xrange(1)]" >100 loops, best of 3: 5.5e+03 usec per loop >[EMAIL PROTECTED]:/usr/lib/python2.3$ python timeit.py -c "[20 for i in >xrange(1)]" >100 loops, best of 3: 4.3e+03 usec per loop > > >Now of course the longer the expressions get, the more time it costs - but >how many long arithmetical expression of constant evaluation value do you >have? > >> >> I agree that things like [time.time() for i in xrange(10)] shouldn't >> be pregenerated and that the problem is more complicated as I thought. >> >> But during compilation the compilor could do an anlysis of the code >> do determine whether there are side effects or not. If the compilor >> then would store a code in the byte code for functions that are >> guaranteed side-effect free and only pregenerated objects generated >> by expressions with no side-effect, some common subexpression >> elimination could be done even in a non-functional language. > >This analysis would only be possible for the most primitive of examples, >the reason beeing that due to the dynamic features syntactically equivalent >expressions can have totally different semantics. So its not really worth >the effort. IOM that doesn't mean there might not be an alternative interesting angle. E.g., what if we had a yield_constant (instant bf here ;-) as well as a yield. IOW an explicit promise that the generator would always yield the same thing for the same input args. This could potentially allow tuple(x for x in foo(1234)) to be pre-calculated, or marked for sticky internal caching or such, if repeat use benefit could not be determined. I guess we can write memoizing decorators now, so how would you e.g., spell memoizing a generator expression? No end to probably impractical ideas ;-) IMO it's more a matter of RO[D]I (return on [development] investment) and restraints on bloat than whether optimizations and other ideas are feasible. I think practicality vs purity drives actual implementation, but purity issues drive a lot of interesting, if not too practical, discussions. Of course, if someone has the energy to become champions of their ideas, and actually implement them for testing and evaluation, more power to them. I don't think we should beat up on Antoon for his interest in exploring theoretical possibilities. Sometimes a spark may fly off and provide some useful illumination. OTOH, interesting is in the eye of the beholder ;-) Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
Re: generator expressions: performance anomaly?
Bengt Richter wrote:
Which make me wonder what plans there are for providing a better
mechanism than default arguments as a way of initializing local function
variables. Nested def's to create a closure with initialized values is
pretty crufty for that, IMO.
What about using a class? Associating functions with data is pretty
much what they're for...
Maybe extending the default argument space
with whatever comes after e.g. a triple star delimiter in the argument list,
but which wouldn't be counted as part of the normal arguments? E.g.,
def foo(x, y=123, *args, **kw, *** i=1, deftime=time.ctime()):
return x*y, kw.get('which_time')=='now' and time.ctime() or deftime
If what you want is to have i=1 and deftime=time.ctime() available
within foo, you could do something like (untested):
class foo(object):
def __init__(self):
self.i = 1
self.deftime = time.ctime()
def __call__(self, x, y=123, *args, **kwds):
return x*y, (kw.get('which_time') == 'now'
and time.ctime() or self.deftime)
foo = foo()
Or if you don't like 'foo = foo()', you could probably abuse the __new__
method (also untested):
class foo(object):
i = 1
deftime = time.ctime()
def __new__(cls, x, y=123, *args, **kwds):
return x*y, (kw.get('which_time') == 'now'
and time.ctime() or self.deftime)
I guess my point is that if you want attribute associated with the
function, it's often easy enough to write a class instead...
Steve
--
http://mail.python.org/mailman/listinfo/python-list
file copy portability
Is shutil.copyfile(src,dst) the *most* portable way to copy files with Python? I'm dealing with plain text files on Windows, Linux and Mac OSX. Thanks! -- http://mail.python.org/mailman/listinfo/python-list
Re: inbuilt function buffer()
Thus spake km ([EMAIL PROTECTED]): > I which context is the inbuilt function buffer() used ? It's an efficiency measure. Say you have a string x. Taking a slice of the string - x[a:a+10] - will implicitly create a new string containing the specified data. Doing the same using buffer - buffer(x, a, 10) - will not. Essentially, buffer() gives you a window into a piece of contiguous data, without the cost of making a copy of the data you want to extract. To see how this might be useful, consider writing a simple web server. The web server reads a local file into memory, and then feeds it bit by bit to a socket until the data is exhausted. Without using buffer, the server would have to create a copy of each snippet of data fed to the socket. Using buffer, however, the copies are avoided, and the data can be consumed more efficently. The code below demonstrates this idea in an elementary fashion - on my system, "takebuf" runs about twice as fast as "take". -- #!/usr/bin/env python2.3 import time SIZE = 1024*1024*50 data = "O"*SIZE def take(data): for i in range(0, SIZE, 1024): yield data[i:i+1024] def takebuf(data): for i in range(0, SIZE, 1024): yield buffer(data, i, 1024) def main(): start = time.time() for i in take(data): pass print "Plain:\t", time.time()-start start = time.time() for i in takebuf(data): pass print "Buffer:\t", time.time()-start if __name__ == "__main__": main() Cheers, Aldo -- Aldo Cortesi [EMAIL PROTECTED] http://www.nullcube.com Off: (02) 9283 1131 Mob: 0419 492 863 -- http://mail.python.org/mailman/listinfo/python-list
Re: Tkinter in thread hangs on windows but not on Linux
Actually, the following link:
http://www.astro.washington.edu/owen/TkinterSummary.html
seems to say my code is illegal - so I'm now just launching a modless
window from the main thread - _seems_ to work
On Tue, 18 Jan 2005 11:45:28 +0100, Philippe C. Martin wrote:
> Hi,
>
> I need to pop-up in a "modless" manner some windows from an existing
> Tkinter loop. The following code works OK under Linux: the second window
> opens, shows the information, and quits cleanly when destroyed. However,
> under windows, I get the second window without the content (so I hang in
> run I guess), and both the thread and the calling process hang.
>
> Any clue ?
>
> Thanks
> Philippe
>
>
>
>
>
> #***
> class SC_DOCS(threading.Thread):
> __m_smg = None
> __m_title = None
> def __init__(self,p_msg,p_title):
> threading.Thread.__init__(self)
> self.__m_msg = p_msg
> self.__m_title = p_title
>
> #***
> def run (self):
> l_r = Tk()
> l_r.title(self.__m_title)
> l_f = Frame(l_r)
> l_f.pack(side=TOP, expand=YES, fill=BOTH)
> l_st = ScrolledText(l_f)
> l_st.pack(side=TOP, expand=YES, fill=BOTH)
> l_st.insert(END,self.__m_msg)
>
> l_r.mainloop()
>
>
> .
> .
> .
>
> l_d = SC_DOCS('A MESSAGE', 'A TITLE')
> l_d.start()
>
>
> .
> .
> .
--
http://mail.python.org/mailman/listinfo/python-list
Re: script to automate GUI application (newbie)
Try following scripting language to automating Windows GUI, it simulates keystrokes (supports most keyboard layouts), simulates mouse movements and clicks and does tons of other stuff: http://www.hiddensoft.com/autoit3/ It works nicely for me. -- http://mail.python.org/mailman/listinfo/python-list
Re: generator expressions: performance anomaly?
On Tue, 18 Jan 2005 09:24:15 -0500, Steve Holden <[EMAIL PROTECTED]> wrote:
[...]
>You probably already know that sensible compiled language systems have
>used constant folding since time immemorial, but Python has always
>eschewed it. That's what comes of being a pragmatist's language: if such
>optimizations really are required the programmer is expected to perform
>them.
Which make me wonder what plans there are for providing a better
mechanism than default arguments as a way of initializing local function
variables. Nested def's to create a closure with initialized values is
pretty crufty for that, IMO. Maybe extending the default argument space
with whatever comes after e.g. a triple star delimiter in the argument list,
but which wouldn't be counted as part of the normal arguments? E.g.,
def foo(x, y=123, *args, **kw, *** i=1, deftime=time.ctime()):
return x*y, kw.get('which_time')=='now' and time.ctime() or deftime
Seem like a minor extension of the default-arg hack.
Regards,
Bengt Richter
--
http://mail.python.org/mailman/listinfo/python-list
Re: Re: Fuzzy matching of postal addresses
Andrew McLean <[EMAIL PROTECTED]> wrote: > > Thanks for all the suggestions. There were some really useful pointers. > > A few random points: > > 1. Spending money is not an option, this is a 'volunteer' project. I'll > try out some of the ideas over the weekend. > ... > I am tempted to try an approach based on splitting the address into a > sequence of normalised tokens. Then work with a metric based on the > differences between the sequences. The simple case would look at > deleting tokens and perhaps concatenating tokens to make a match. Do please have a look at the Febrl project at http://febrl.sf.net We would be most interested to learn how well its HMM address parser works well for all those "quaint" English addresses, and its Fellegi-Sunter probabilistic matching engine should give good results on your data (or use the simpler deterministic engine if you like). Provided that your data are not too large (eg more than a few hundred thousand records), Febrl should work fairly well. We'd be pleased to get any feedback you may have. Tim C -- http://mail.python.org/mailman/listinfo/python-list
Re: lambda
On 18 Jan 2005 13:28:00 GMT, Antoon Pardon <[EMAIL PROTECTED]> wrote: >Op 2005-01-18, Nick Coghlan schreef <[EMAIL PROTECTED]>: >> Antoon Pardon wrote: >>> More specific the Decimal class is mutable and usable as dict key. >> >> It's *meant* to be immutable though. The fact that we used __slots__ instead >> of >> __setattr__ to implement the immutability, so you *can* overwrite the slot >> variables if you really want to is merely an artifact of the current Python >> implementation. >> >> The limited mutability bug will disappear in Python 2.5, so it's not a good >> example of a 'mutable' dict key (especially given that the only way to >> mutate it >> is to modify private variables directly). >> >> And, as I've stated previously, if the issue of sane mutable keys in >> dictionaries and sets really bugs you so much - implement identity_dict and >> identity_set in C and lobby for their inclusion in the collections module. > >I'm not bugged by its absence in Python. I'm bugged by the attitude >about them. But anyway I'm thinking about implementing a safe dictionary >that will copy whenever it would otherwise allow the risk of mutating a >key. I encourage you to do it. It should be a rich learning experience. My bet is you will discover something about the real requirements of what you are "thinking about implementing" ;-) IANAP, but ISTM that after a certain point, trying to get made-my-point satisfaction in a thread like this is more like OCD symptomatology than n.g. dialog ;-) > >> On the more general point of "don't use mutable objects with non-identity >> based >> comparisons as dictionary keys", try teaching students for a while (or >> listen to >> those who have): > >What kind of students? > >I have implemented a hash table when I was a student and its >implementation allowed the use of 'mutable' objects as a key >without a problem. It simply always made copies when appropiate >and didn't allow external access to the keys. So although the >key objects were 'mutable' there was no way a user could accidently >mutate a key. This is word play IMO. What you describe is effectively using the mutables to construct immutable keys for actual use, not using immutable keys. Having the immutable (because of access restriction) constructed keys allows you to check on their consistency with their source any time you want, but that doesn't change the fact that you have created an alternative dictionary implementation with immutable keys made immutable by copying and access restriction. If you update your dictionary when a key no longer matches its source data, you are just deleting an immutable-by-special-means key and entering the associated value in association with a new immutable-by-special-means key. I can produce OCD symptoms too ;-) > >So don't use a mutable as a dictionary key isn't so much a dictionary >limitation in general but a specific limitation of the python implementation. > >And yes I understand, the current implenatation is the result of the >fact that the same dictionaries are used internally for variables in >scopes and attributes in objects and the fact that no copies are >involved gives a boost to performance. But it could be argued that >providing these same dictionaries with those semantics to the users >was a premature optimisation. If you see a sign like +-> | WILD GOOSE CHASE THIS WAY-> +-> || ||\|/ ||=o= ||/|\ .`.||,..__|_,. Do you feel that you must make sure? The sign painter may only be indicating what his own experience was, after all. But if it was a core developer's experience, it may be prudent to bet on another trail -- unless you have an extremely interesting hunch. Then you should follow your passion and have your own experience, and you may wind up being able to contribute something (even if only an exclamation point on the sign ;-) > >> When stating useful general principles, it is never, ever worth it to get >> into >> the quibbly little details about exceptions to the principle. If students >> ask, >> admit that they exist, but point out that the exceptions are rare, and not >> worth >> worrying about at that point in their learning. > >But don't use mutable keys is not a general principle. It is a principle >introduced by the limitations of the python implementations. That is so in your mind, and it is so given certain interpretations of the words you are using, but to others "mutable keys" may be a contradiction in terms, because they do not use the words in the same sense as you. If you can't see alternative conceptual constructs you are stuck, and if we can't agree on the meaning of words for a given dialog, we won't be communicating very well. The difficulty is getting people to recognize their implicit assumptions and definitions ;-) > >I don't like it when a good rule of thumb because of implementation >limitations is sold as a general
Re: Assigning to self
Marc 'BlackJack' Rintsch wrote: Frans Englich wrote: Then I have some vague, general questions which perhaps someone can reason from: what is then the preferred methods for solving problems which requires Singletons? As already mentioned it's similar to a global variable. If I need a "Singleton" I just put it as global into a module. Either initialize it at module level or define a function with the content of your __init__(). If one is determined to both use a Singleton and avoid having a plain module-global variable, one could (ab)use function default parameters: class __Foo: "I am a singleton!" pass def Foo(foo_obj = __Foo()): assert isinstance(foo_obj, __Foo return foo_obj Of course, this suffers from the weakness that one might pass an object as an argument to the factory function and thus temporarily override the Singleton-ness of __Foo... but a determined programmer will work around any sort of protection scheme anyhow. ;) In general, ISTM that if one wants a Singleton, it's best to create it via a factory function (even if that function then masquerades as a class). This gives you pretty good control over the circumstances in which your Singleton will be created and/or retrieved, and it also makes it trivial to replace the Singleton with some other pattern (such as, e.g., a Flyweight or Borg object) should the need to refactor arise. Jeff Shannon Technician/Programmer Credit International -- http://mail.python.org/mailman/listinfo/python-list
Re: Fuzzy matching of postal addresses
"Andrew McLean" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] Thanks for all the suggestions. There were some really useful pointers. A few random points: 1. Spending money is not an option, this is a 'volunteer' project. I'll try out some of the ideas over the weekend. 2. Someone commented that the data was suspiciously good quality. The data sources are both ones that you might expect to be authoritative. If you use as a metric, having a correctly formatted and valid postcode, in one database 100% the records do in the other 99.96% do. 3. I've already noticed duplicate addresses in one of the databases. 4. You need to be careful doing an endswith search. It was actually my first approach to the house name issue. The problem is you end up matching "12 Acacia Avenue, ..." with "2 Acacia Avenue, ...". I am tempted to try an approach based on splitting the address into a sequence of normalised tokens. Then work with a metric based on the differences between the sequences. The simple case would look at deleting tokens and perhaps concatenating tokens to make a match. It's been a while since I did this stuff. The trick in dealing with address normalization is to parse the string backwards, and try to slot the pieces into the general pattern. In your case, the postal code, district (is that what it's called in the UK?) and city seem to be fine, it's when you get to the street (with or without house number), building name and flat or room number that there's a difficulty. We always had a list of keywords that could be trusted to be delimiters. In your examples, "the" should be pretty reliable in indicating a building name. Of course, that might have some trouble with Tottering on the Brink. John Roth -- Andrew McLean -- http://mail.python.org/mailman/listinfo/python-list
Re: simultaneous multiple requests to very simple database
"Eric S. Johansson" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > 99.9 percent of what I do (and I suspect this could be true for others) > could be satisfied by a slightly enhanced super dictionary with a record > level locking. BUT - Did you not mention! : > Estimated number of records will be in the ballpark of 50,000 to 100,000 in his > early phase and 10 times that in the future. Each record will run about > 100 to 150 bytes. . And > The very large dictionary must be accessed from > multiple processes simultaneously And > I need to be able to lock records > within the very large dictionary when records are written to And > although I must complete processing in less than 90 seconds. And - the hole in the bottom of the hull - all of the above using "a slightly enhanced super dictionary". *Super* dictionary??? *Slightly* enhanced??? Have you attempted any feasability tests? Are you running a Cray? There are many database systems available, and Python (probably) has free bindings to every one of them. Whichever one might choose, it would add simplicity, not complexity to what you are attempting. The problems you mention are precisely those that databases are meant to solve. The only tough (impossible?) requirement you have is that you don't want to use one. When you write that "super dictionary", be sure to post code! I could use one of those myself. Thomas Bartkus -- http://mail.python.org/mailman/listinfo/python-list
Re: simultaneous multiple requests to very simple database
Ricardo Bugalho wrote: On Tue, 18 Jan 2005 17:33:26 -0500, Eric S. Johansson wrote: When I look at databases, I see a bunch of very good solutions that are either overly complex or heavyweight on one hand and very nice and simple but unable to deal with concurrency on the other. two sets of point solutions that try to stretch themselves and the developers to fit other application contexts. Have you considerded SQLite/pySQLite ? yep and apparently it won't work http://www.sqlite.org/faq.html#q7 if I had record level locking, the code would do a very common pattern like: if record present: Lock record modify record release lock else: create record atomically (actual method TBB) if I read their opinion correctly, the SQL lite folks are wrong in that only the applications need massive concurrency. Small applications need significant to massive concurrency for very tiny windows on very little data. but I do appreciate the pointer. -- http://mail.python.org/mailman/listinfo/python-list
Re: Assigning to self
In <[EMAIL PROTECTED]>, Frans Englich wrote: > Then I have some vague, general questions which perhaps someone can reason > from: what is then the preferred methods for solving problems which requires > Singletons? As already mentioned it's similar to a global variable. If I need a "Singleton" I just put it as global into a module. Either initialize it at module level or define a function with the content of your __init__(). Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: macros
On Tue, 18 Jan 2005 14:36:08 -0800, Jeff Shannon wrote: > I think that this sort of thing is better to have as an explicitly > risky hack, than as an endorsed part of the language. The mere fact > that this *is* something that one can clearly tell is working around > certain deliberate limitations is a big warning sign, and it makes it > much less likely to be used extensively. Relatively few people are > going to want to use something called "bytecodehacks" in a > mission-critical piece of software, compared to the number who'd be > perfectly happy to use a language's built-in macro facilities, so at > least it keeps the actual usage down to a somewhat more manageable level. > > To rephrase this a bit more succinctly ;) there's a big difference > between having no practical way to prevent something, and actually > encouraging it. Hey, argument, there you are. I figured you'd work your way out somehow without me having to type you. :-) The counterargument that leaps to mind is that if enough people do it, there's a need, and that need should be met explicitly rather than with "hacks", for the benefit of all. Again, I emphasize my ambivalence. Are there "enough"? (It's hard to tell, maybe if it weren't so hard more would do it.) Is the benefit big enough? Is "the need" the need to tell people "stop juggling chainsaws!"? (In which case I guess "the need" has been met.) Basically, I'm willing to trust Guido overall on the grounds that he has earned it. But I still can't help but wonder if outright dismissal isn't missing something that could be useful and positive if Guido et al turned their minds to it. But then, I have no idea what it may be and it may be impossible. Like I said, I'm torn on this one :-) -- http://mail.python.org/mailman/listinfo/python-list
Re: macros
Jeremy Bowers wrote:
You know, Guido might as well give in now on the Macro issue. If he
doesn't come up with something himself, apparently we'll just hack
bytecode.
Ah, hacking bytecode isn't where it's at anymore. These days, you use
the compiler package and munge the AST. Hygenic!
That said, the big brake on macros implemented either of these ways is
the fact that the source still has to be syntactically valid python.
You can make a macro FOOBAR that works in these ways:
x = FOOBAR(some, arguments) # Pseudo-function
if FOOBAR:
a.suite # Pseudo-'if' statement
{ FOOBAR: expr } # Pseudo-throwaway dict
...but not these:
FOOBAR:
a.suite # Suite that explicity depends on FOOBAR for meaning
x = a FOOBAR b # expression with pseudo-keyword
What we need is a generic suite statement, something like:
gensuite ::= [decorators] "do:" suite
...where the suite is treated like the body of an anonymous function
that is called and discarded immediately after it is defined. In other
words, the code
@f2
do: pass
...is roughly equivalent to:
@f2
def (): pass
()
del
Then we could abuse the heck out of it by perverting the AST of
@FOOBAR
do:
stuff
That's never going to happen, tho.
Cheers,
Evan @ 4-am
--
http://mail.python.org/mailman/listinfo/python-list
Re: simultaneous multiple requests to very simple database
On Tue, 18 Jan 2005 17:33:26 -0500, Eric S. Johansson wrote: > When I look at databases, I see a bunch of very good solutions that are > either overly complex or heavyweight on one hand and very nice and simple > but unable to deal with concurrency on the other. two sets of point > solutions that try to stretch themselves and the developers to fit other > application contexts. > Have you considerded SQLite/pySQLite ? -- Ricardo -- http://mail.python.org/mailman/listinfo/python-list
python/cgi/html bug
Hi.
I've written a cgi messageboard script in python, for an irc chan I happen
to frequent.
Bear with me, it's hard for me to describe what the bug is. So I've
divided this post into two sections: HOW MY SCRIPTS WORKS, and WHAT THE
BUG IS.
HOW MY SCRIPT WORKS
Basically, it's divided into two executable scripts..
One is the thread viewer, ppthread.py, which views threads. When someone
posts a new topic, for instance called "Generic new topic", it creates
a file called "Generic new topic.thread". It stores the post, and any
subsequent posts under in the thread in that file. Nice and simple I
figured.
The other executable script is the topic viewer, pptopic.py. All that does
is display the topics, by doing a "tops = os.popen('ls -c *.thread')" The
"ls -c" part reads the threads in the order in which they've been
modified, so the first item in the list is always the thread most recently
posted in.
It then creates an html link to each of the threads ... on the page the
html looks like
foo
WHAT THE BUG IS
The problem is when someone posts a new topic, and that topic happens to
have "" double quotes, or any other strange character, some strange
glitches occur.
Best way to describe is to demonstrate it is go to the forum and try
it yourself. Try entering a topic with straight, ordindary characters, not
that you can re enter the thread any time you want and make new posts
under it. Then try entering a thread with new or whacky characters and see
how far you get.
http://funkmunch.net/~pirch/cgi-bin/alphaforum/pptopic.py
BTW, if you want to download the script, here it is in gzipped form
http://funkmunch.net/~pirch/pepperpot.tgz
--
http://mail.python.org/mailman/listinfo/python-list
Re: simultaneous multiple requests to very simple database
On Tue, 18 Jan 2005 17:33:26 -0500, Eric S. Johansson <[EMAIL PROTECTED]> wrote: > so in conclusion, my only reason for querying was to see if I was > missing a solution. So far, I have not found any work using because > they add orders of magnitude more complexity than simple dbm with file > locking. Obviously, the simple solution has horrible performance right > now I need simplicity implementation. > > thanks for your commentary. Maybe you can just get the best of both worlds. Have a look at SQLObject. You can ignore the fact that underneath the SQLObject there's a postgres (or mysql, or whatever) database, and get OO based persistance. SQLObject is crippled in that there are degrees of freedom that SQL gives you that SQLObject takes away/makes hard to use, but what you're trying to do, and what most people actually do with databases, can be easily wrapped around with a simple, pythonic wrapper. It even has a .createTable() function for those times when you don't even want to log into the database. Regards, Stephen Thorne. -- http://mail.python.org/mailman/listinfo/python-list
Re: lambda
Antoon Pardon <[EMAIL PROTECTED]> writes: > Op 2005-01-18, Simon Brunning schreef <[EMAIL PROTECTED]>: > > On 18 Jan 2005 07:51:00 GMT, Antoon Pardon <[EMAIL PROTECTED]> wrote: > >> 3 mutating an item in a sorted list *does* *always* cause problems > > > > No, it doesn't. It might cause the list no longer to be sorted, but > > that might or might no be a problem. > > Than in the same vain I can say that mutating a key in a dictionary > doesn't always cause problems either. Sure it may probably make a > key unaccessible directly, but that might or might not be a problem. Well, I'd definitely consider an inaccessible key as constituting a problem, but I don't think that's a good analogy to the list case. With the dictionary, the change can (though I do agree it does not have to) interfere with proper operation of the dictionary, while a list that is no longer sorted still functions perfectly well as a list. That is, I feel "problems" are more guaranteed with a dictionary since we have affected base object behavior, whereas sorted is not an inherent attribute of the base list type but something the application is imposing at a higher level. For example, I may choose to have an object type that is mutable (and not worthy for use as a dictionary key) but maintains a logical ordering so is sortable. I see no problem with sorting a list of such objects, and then walking that list to perform some mutation to each of the objects, even if along the way the mutation I am doing results in the items so touched no longer being in sorted order. The act of sorting was to provide me with a particular sequence of objects, but aside from that fact, the list continues to perform perfectly well as a list even after the mutations - just no longer delivering objects in sorted order. -- David -- http://mail.python.org/mailman/listinfo/python-list
Re: Fuzzy matching of postal addresses
Thanks for all the suggestions. There were some really useful pointers. A few random points: 1. Spending money is not an option, this is a 'volunteer' project. I'll try out some of the ideas over the weekend. 2. Someone commented that the data was suspiciously good quality. The data sources are both ones that you might expect to be authoritative. If you use as a metric, having a correctly formatted and valid postcode, in one database 100% the records do in the other 99.96% do. 3. I've already noticed duplicate addresses in one of the databases. 4. You need to be careful doing an endswith search. It was actually my first approach to the house name issue. The problem is you end up matching "12 Acacia Avenue, ..." with "2 Acacia Avenue, ...". I am tempted to try an approach based on splitting the address into a sequence of normalised tokens. Then work with a metric based on the differences between the sequences. The simple case would look at deleting tokens and perhaps concatenating tokens to make a match. -- Andrew McLean -- http://mail.python.org/mailman/listinfo/python-list
Re: macros
Jeremy Bowers wrote: On Tue, 18 Jan 2005 12:59:07 -0800, Robert Brewer wrote: You know, Guido might as well give in now on the Macro issue. If he doesn't come up with something himself, apparently we'll just hack bytecode. I'm not sure that's a gain. I think that this sort of thing is better to have as an explicitly risky hack, than as an endorsed part of the language. The mere fact that this *is* something that one can clearly tell is working around certain deliberate limitations is a big warning sign, and it makes it much less likely to be used extensively. Relatively few people are going to want to use something called "bytecodehacks" in a mission-critical piece of software, compared to the number who'd be perfectly happy to use a language's built-in macro facilities, so at least it keeps the actual usage down to a somewhat more manageable level. To rephrase this a bit more succinctly ;) there's a big difference between having no practical way to prevent something, and actually encouraging it. Jeff Shannon Technician/Programmer Credit International -- http://mail.python.org/mailman/listinfo/python-list
How to fill available screen size then scroll
Hi all, I am writing a gui that expands depending on the number of interefaces a user decides to use with Win 2k, Tkinter, and Pmw. So with normal use the gui window will expand to the screen size and then clip without scrolling. If I use Pmw.ScrolledFrame, the clipping frame is set based on the size of the first child frame and never expands to fill the screen. It just expands the size of the inside frame inside the clipping frame. I need a tweener solution. I need the gui to expand until it reaches the width of the available viewing screen. THEN the scroll bar kicks in with a clipping frame the width of the screen to allow the user to see as many interfaces as possible. Does anyone know how to do this? Thanks ahead of time, Marc -- http://mail.python.org/mailman/listinfo/python-list
Re: simultaneous multiple requests to very simple database
Thomas Bartkus wrote: "Eric S. Johansson" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] at this point, I know they will be some kind souls suggesting various SQL solutions. While I appreciate the idea, unfortunately I do not have time to puzzle out yet another component. Someday I will figure it out because I really liked what I see with SQL lite but unfortunately, today is not that day (unless they will give me their work, home and cell phone numbers so I can call when I am stuck. ;-) Forgive me if this reply sounds a bit glib. But I do mean it without malice. understood and taken in that spirit. Do you seriously expect to write your own (database) solution and that this will save you time and effort over learning an existing (SQL) solution? Because - If you are seeking to "save time" on "puzzles", you are certainly going about it the wrong way. one thing I learned a long time ago was to respect the nagging voice in the back of my head that says "there is something wrong". Right now with databases, that voice is not nagging but screaming. So I made my query to try and prove that intuition wrong. So far, that has not happened. When I look at databases, I see a bunch of very good solutions that are either overly complex or heavyweight on one hand and very nice and simple but unable to deal with concurrency on the other. two sets of point solutions that try to stretch themselves and the developers to fit other application contexts. 99.9 percent of what I do (and I suspect this could be true for others) could be satisfied by a slightly enhanced super dictionary with a record level locking. but, the database world does not fit this model. It has a great deal more complication then what is frequently necessary. If I ever find the time, I will try to build such a beast probably around Metakit. The only reason for reluctance is that I have spent too many hours tracking down concurrency problems at the OS level way to many years ago and so I do not create multithreaded applications lightly. so in conclusion, my only reason for querying was to see if I was missing a solution. So far, I have not found any work using because they add orders of magnitude more complexity than simple dbm with file locking. Obviously, the simple solution has horrible performance right now I need simplicity implementation. thanks for your commentary. ---eric -- http://mail.python.org/mailman/listinfo/python-list
Re: extension module, thread safety?
Nick Coghlan <[EMAIL PROTECTED]> writes: > Pierre Barbier de Reuille wrote: > > Ok, I wondered why I didn't know these functions, but they are new > > to Python 2.4 ( and I didn't take the time to look closely at Python > > 2.4 as some modules I'm working with are still not available for > > Python 2.4). But if it really allows to call Python code outside a > > Python thread ... then I'll surely use that as soon as I can use > > Python 2.4 :) Thanks for the hint :) > > The Python 2.4 docs claim the functions were added in Python 2.3, even > though they aren't documented in the 2.3.4 docs. > > The 2.3 release PEP (PEP 283) confirms that PEP 311 (which added these > functions) went in. And even before that it was certainly possible to call into the Python interpreter from a native thread using existing functions, albeit the newer functions are more convenient (and perhaps more robust, I don't know). My earliest interaction with Python (~1999, while writing a module that extended and embedded Python 1.5.2) used PyEval_AcquireThread() and PyEval_ReleaseThread() to get access to a thread state from a native C application thread (not initiated by the Python interpreter) to allow me to call safely into an executing Python script upon asynchronous data reception by the C code. -- David -- http://mail.python.org/mailman/listinfo/python-list
Re: simultaneous multiple requests to very simple database
"Eric S. Johansson" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > at this point, I know they will be some kind souls suggesting various > SQL solutions. While I appreciate the idea, unfortunately I do not have > time to puzzle out yet another component. Someday I will figure it out > because I really liked what I see with SQL lite but unfortunately, today > is not that day (unless they will give me their work, home and cell > phone numbers so I can call when I am stuck. ;-) Forgive me if this reply sounds a bit glib. But I do mean it without malice. Do you seriously expect to write your own (database) solution and that this will save you time and effort over learning an existing (SQL) solution? Because - If you are seeking to "save time" on "puzzles", you are certainly going about it the wrong way. Best of luck Thomas Bartkus -- http://mail.python.org/mailman/listinfo/python-list
Re: Fuzzy matching of postal addresses
John Machin wrote: > Ermmm ... only remove "the" when you are sure it is a whole word. Even > then it's a dodgy idea. In the first 1000 lines of the nearest address > file I had to hand, I found these: Catherine, Matthew, Rotherwood, > Weatherall, and "The Avenue". > Partial apologies: I wasn't reading Skip's snippet correctly -- he had "THE ", I read "THE". Only "The Avenue" is a problem in the above list. However Skip's snippet _does_ do damage in cases where the word ends in "the". Grepping lists of placenames found 25 distinct names in UK, including "The Mythe" and "The Wrythe". Addendum: Given examples in the UK like "Barton in the Beans" (no kiddin') and "Barton-on-the-Heath", replacing "-" by space seems indicated. -- http://mail.python.org/mailman/listinfo/python-list
anydbm biasing
I have a preference for gdbm when building DBM based dictionaries but
have found I cannot count on it being there all the time. Therefore, I
have created this little tidbit which you call before opening your
anydbm database to bias the preference towards gdbm instead of dbhash:
# bias DBM towards gdbm if at all possible.
def bias_anydbm():
"""bias anydbm to gdbm"""
try:
_mod = __import__("gdbm")
except ImportError:
pass
else:
# and other words, if you can import gdbm, make it the default
anydbm._defaultmod = _mod
usage:
bias_anydbm()
open_DBM = anydbm.open(DBM_path, 'c')
if you have gdbm enabled, it will use that otherwise it will default to
the search list in anydbm. obviously, this can be used to bias anydbm
to meet your own preferences
---eric
--
http://mail.python.org/mailman/listinfo/python-list
Re: Contributor's List
<[EMAIL PROTECTED]> wrote: ... > Is this mean't to only cover additional entries which were added in > the 2nd edition, or is it also mean't to encompass entries which were > carried over from the 1st edition as well. The latter: it covers all entries. > If it is both, then the editing must have been quite cut throat as I It was indeed. Fewer than half of the recipes in the 2nd edition are "carried over" (with heavy edits in all cases) from the first. > dropped from 3 entries in the 1st edition to 0 in the 2nd edition. True, alas: your three recipes in the Distributed Processing chapter were dropped. Not light-heartedly, believe me. > I can sort of understand if the intent was to get rid of entries which It was of course not my intent to *GET RID* of anything whatsoever: I selected all the recipes for the 1st edition, just as for the 2nd one, and would dearly have loved to keep each and every one of them (I wouldn't have selected them in the first place if I didn't like them). The INTENT was to add over a couple hundred new and (I do believe) wonderful recipes; the CONSTRAINT was that I couldn't just blithely double the book's size. So, the only way to make space for the new was to ruthlessly cut much of the old, in order to limit the book's size within reasonable boundaries. > referenced packages which weren't regarded as mainstream. I guess > it is only 14 years of work down the drain. ;-( I wish you wouldn't look on it that way. The Python Cookbook is not intended as a validation or invalidation of any particular piece of software -- just, if you will, as a reflection of how widespread the current interest on it is. Consider: _my_ own lovechild "non-mainstream" package is gmpy, OK? Well, I didn't put even ONE recipe about it in either edition nor on the online Cookbook -- nor did anybody else post recipes using it to the Cookbook, validating my belief that it's too specialized to cover in the book. I don't consider this means "years of work down the drain": gmpy scratches the itch I made it for, and occasional references to others using it are just a little extra bonus, even if they do make my heart give a little jump of joy each time I see one. I think that's the spirit in which to do open-source development... Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: pickling extension class
harold fellermann <[EMAIL PROTECTED]> writes:
> Hi all,
>
> I have a problem pickling an extension class. As written in the
> Extending/Embedding Manual, I
> provided a function __reduce__ that returns the appropreate tuple.
> This seams to work fine,
> but I still cannot pickle because of the following error:
>
> >>> from model import hyper
> >>> g = hyper.PeriodicGrid(4,4,1)
> >>> g.__reduce__()
> (,(4.,4.,1.))
> >>> import pickle
> >>> pickle.dump(g,file("test","w"))
> Traceback (most recent call last):
>File "pickle_test.py", line 5, in ?
> pickle.dump(g,file("test","w"))
>File "/sw/lib/python2.4/pickle.py", line 1382, in dump
> Pickler(file, protocol, bin).dump(obj)
>File "/sw/lib/python2.4/pickle.py", line 231, in dump
> self.save(obj)
>File "/sw/lib/python2.4/pickle.py", line 338, in save
> self.save_reduce(obj=obj, *rv)
>File "/sw/lib/python2.4/pickle.py", line 414, in save_reduce
> save(func)
>File "/sw/lib/python2.4/pickle.py", line 293, in save
> f(self, obj) # Call unbound method with explicit self
>File "/sw/lib/python2.4/pickle.py", line 760, in save_global
> raise PicklingError(
> pickle.PicklingError: Can't pickle : it's
> not found as hyper.PeriodicGrid
> >>> dir(hyper)
> ['Dir', 'Neighbors', 'PeriodicGrid', 'PeriodicPos', '__doc__',
> '__file__', '__name__', 'refcount']
> >>> hyper.PeriodicGrid
>
^
I think that's your error. The extension type is declared to be
hyper.PeriodicGrid, where it actually is model.hyper.PeriodicGrid
(because hyper is in the model package).
Pickle stores g.__class__.__module__ (which is "hyper") and
g.__class__.__name__ (="PeriodicGrid") to find the class object for
reimporting, and on unpickling, tries to do __import__("hyper"), which
fails.
The tp_name slot of your extension type should be "model.hyper.PeriodicGrid".
--
|>|\/|<
/--\
|David M. Cooke
|cookedm(at)physics(dot)mcmaster(dot)ca
--
http://mail.python.org/mailman/listinfo/python-list
macros (was: RE: generator expressions: performance anomaly?)
On Tue, 18 Jan 2005 12:59:07 -0800, Robert Brewer wrote: > Especially since you can already do it explicitly with Raymond > Hettinger's cookbook recipe: > http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/277940 You know, Guido might as well give in now on the Macro issue. If he doesn't come up with something himself, apparently we'll just hack bytecode. I'm not sure that's a gain. (To be fair, I can see some arguments that it is, so that "I'm not sure" isn't a passive-aggressive/sarcastic snipe like most people use it in this context; I mean it literally.) (I expect if we ever do see them, this will be the basic argument used. I guess you could call it Historic Inevitably. :-) ) I'm not just basing it on this one thing, I'm basing this on all the bytecode hacks I've seen. -- http://mail.python.org/mailman/listinfo/python-list
Re: what would you like to see in a 2nd edition Nutshell?
Steven Chan <[EMAIL PROTECTED]> wrote: > I completely agree. I'm also waiting for an advanced Python/project > management book that helps folks out with large-scale projects. I won't schedule that project until the Nutshell 2nd ed is substantially done... and I'm not _promising_ I'll schedule it right afterwards;-). > And, for the 2nd edition, may I suggest: > - coverage of OptionParser module, which is more advanced than the > getopt module that you discuss on page 141. I assume you mean optparse -- that's the module; OptionParser is a class within that module. Yep, covering that is in the plan. > - better Mac OS X application building coverage. Tell us how to build > double-clickable applications. Python in a Nutshell is a book about *cross-platform* Python. There is practically no *WINDOWS*-specific coverage -- 80% of the market or whatever -- it would be absurd if there was platform-specific coverage for a (wonderful) system that has less than 1/10th as much volume (and much as I may be rooting for the mac mini to revolutionize the market, I suspect it will only make a relatively small, incremental difference). I *WISH* I could write a book about Python on the Mac -- ever since I got my iBook, over a year ago, it's been my love and joy, and as soon as I had to change a desktop machine I got myself a dual processor G5 PowerMac too. However, when I proposed that idea to O'Reilly, their reaction was a firm no -- it's too narrow a market, they think (and, being the premier publisher for both the Mac AND Python, they should know, if anybody does). I don't know if this perception of O'Reilly can be changed. If it ever does change, I sure hope they'll call me first, to do that book...!!! > I wish I could ask for wxPython coverage (the whole chapter on tkinter > is useless to me), but I won't start a flame war here. As long as Tkinter is distributed with standard Python and not deprecated, it's unlikely that a reference work about Python can just quietly ignore it. If standard Python changed in this respect, I would of course take that into account in the next following edition!-) Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: Tkinter in thread hangs on windows but not on Linux
Well this is what is on the top of my script: from Tkinter import * import threading from ScrolledText import * I still hang under XP wish I had 2K to test. I almost sounds like tkinter does not get refresh events anymore. I'll keep at it On Tue, 18 Jan 2005 12:42:21 -0800, Kamilche wrote: > This example worked for me on Windows 2000, after inserting > > import threading > from Tkinter import * > import ScrolledText > > > at the top. -- http://mail.python.org/mailman/listinfo/python-list
Re: what would you like to see in a 2nd edition Nutshell?
kery <[EMAIL PROTECTED]> wrote: ... > Any schedule for publication of 2nd Ed? I just bought 1st Ed. The 2nd edition Python Cookbook appears to be on-track for PyCon (late March) for the very first ink-on-paper -- probably April in bookstores. The 2nd edition Python in a Nutshell is more doubtful, being just started and all that -- OSCON is a possible target, but it's way too early to say if I'll manage to hit it. In both cases, the 2nd ed is meant to focus on versions 2.3 and 2.4 of Python, while the 1st ed covered all versions up to 2.2 included. So, if you're still interested in using Python 2.2 or older versions, you may want to stock up on 1st editions of Cookbook and Nutshell; if you're only interested in 2.3 and following versions, in the case of the Cookbook waiting 2-3 months for the 2nd ed may be worth it, while, in the case of the Nutshell, I would definitely not recommend a far longer and more uncertain waiting period of 7 months or more. Moreover, the changes in the Nutshell will be less than those in the Cookbook were: the Cookbook has changed way more than 50% of its contents, the Nutshell will change substantially less (according to current plans: I'll be able to give more precise information later this year). Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: script to automate GUI application (newbie)
In article <[EMAIL PROTECTED]>, Jim <[EMAIL PROTECTED]> wrote: > >It sounds like a case for the Expect program, to me. Try Google-ing >for "Expect". If you are looking for a Python approach, then try >googling for "Expect Python". > >Jim > No--that is, I find his description unambiguous in NOT allowing for "keyboard control", which is Expect's domain. Expect, of any flavor, will not help. Along with the Java-savvy solutions already mentioned, several general-purpose record-playback tools are available for Windows. http://wiki.tcl.tk/8813 > mentions several. -- http://mail.python.org/mailman/listinfo/python-list
Re: Excel module for Python
I generate a lot pseudo excel file. Just write row by row on file and separate every cell of a row by a tab and put an .xls extension on the file name. When you double click. It opens directly EXCEL and you have directly the column and the row. It is easier than the CSV or SYLK files. If you want to format it automatically you can either define a VBA macro or use python com. Cheers, Jean-Paul -- http://mail.python.org/mailman/listinfo/python-list
RE: generator expressions: performance anomaly?
Jeremy Bowers wrote: > On Tue, 18 Jan 2005 14:05:15 +, Antoon Pardon wrote: > > I don't see how generating byte code for a = 9; when seeing the > > expression a = 3 + 6, would be a problem for non-functional > > languages. > > Ultimately, the use is fairly limited; I can't imagine the > execution time saved would reach the time of implementation > for weeks after a release, even aggregating across all Python > use in the world, and "real time gained" (i.e., time useful > to a human) would probably never add up to the > implementation time. So why bother? That's a horrid trade off > when there are so many other real gains to be had. Especially since you can already do it explicitly with Raymond Hettinger's cookbook recipe: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/277940 Robert Brewer MIS Amor Ministries [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: pickling extension class
harold fellermann <[EMAIL PROTECTED]> wrote:
...
> Here it goes...:
> OOPS, error (exceptions.ImportError): No module named hyper
So, the __import__ in pickle fails -- indeed, __import__('foo') when
'foo' ``is imported from a subpackage'' is _supposed_ to fail, as
'hyper' is not the name you SHOULD be importing. For example,
__import__('email.Encoders')
is fine, but just
__import__('Encoders')
fails with ImportError -- there IS no toplevel module by that name!
> I have noticed that the error does not occur, when the imported module
> ('hyper') is in the same directory as the script that pickles. When it
> is imported from a subpackage (like in the code
> I sent you) it goes wrong.
If you can't fix the modulename given by your type, you can perhaps
kludge things up by (e.g.)
import the.real.hyper
sys.modules['hyper']=the.real.hyper
before you pickle; but I suspect UNpickling would fail in that case.
Using the standard library copy_reg module to register your way to
pickle and recover instances of your type might work better.
Alex
--
http://mail.python.org/mailman/listinfo/python-list
Re: Tkinter in thread hangs on windows but not on Linux
This example worked for me on Windows 2000, after inserting import threading from Tkinter import * import ScrolledText at the top. -- http://mail.python.org/mailman/listinfo/python-list
Window capture using WM_PRINT and Python
Hi !
I'm a Java developper and I wish to make a capture of an offscreen
window (on WinXP). It's not possible in Java, so I use a python script
and WM_PRINT, but it doesn't seem to work.
Could someone have a look at my script and give me any advise ?
TIA
--
Arnaud
my python script : python snap.py GraphicalContext_handle image_handle
--
snap.py :
"
import win32api, win32con, sys
win32api.SendMessage(sys.argv[2], win32con.WM_PAINT, sys.argv[3], 0)
win32api.SendMessage(sys.argv[2], win32con.WM_PRINT, sys.argv[3],
win32con.PRF_CHILDREN | win32con.PRF_CLIENT | win32con.PRF_OWNED)
"
snippet from Snapshot.java :
"
public static Image snapshot(Composite bean) {
GC gc = new GC(bean);
final Image image = new Image (null, bean.getBounds().width,
bean.getBounds().height);
String commmand = "python snap.py " + gc.handle + " " + image.handle;
Runtime rt = Runtime.getRuntime();
try {
Process p = rt.exec(command);
} catch (.)
gc.dispose();
return image;
}
"
--
http://mail.python.org/mailman/listinfo/python-list
Re: hex notation funtion
tertius wrote: Hi, Is there a builtin function that will enable me to display the hex notation of a given binary string? (example below) Thanks all. -- http://mail.python.org/mailman/listinfo/python-list
Re: One-Shot Property?
Leif K-Brooks wrote:
class CachingProperty(object):
def __init__(self, attr_name, calculate_function):
self._name = attr_name
self._calculate = calculate_function
def __get__(self, obj, type=None):
if obj is None:
return self
else:
value = self._calculate(obj)
setattr(obj, self._name, value)
return value
And example code:
>>> class Foo(object):
... def calculate_value(self):
... print 'Calculating...'
... return 42
... foo = CachingProperty('foo', calculate_value)
...
>>> bar = Foo()
>>> bar.__dict__
{}
>>> bar.foo
Calculating...
42
>>> bar.foo # Notice that the print statement doesn't run this time
42
>>> bar.__dict__
{'foo': 42}
To build on this for Python 2.4:
class Caches(object):
def __init__(self, calculate_function):
self._calculate = calculate_function
def __get__(self, obj, _=None):
if obj is None:
return self
value = self._calculate(obj)
setattr(obj, self._calculate.func_name, value)
return value
class Foo(object):
@Caches
def foo(self):
print 'Calculating...'
return 42
--Scott David Daniels
[EMAIL PROTECTED]
--
http://mail.python.org/mailman/listinfo/python-list
Re: hex notation funtion
Grant Edwards wrote:
On 2005-01-18, Grant Edwards <[EMAIL PROTECTED]> wrote:
On 2005-01-18, tertius <[EMAIL PROTECTED]> wrote:
Is there a builtin function that will enable me to display the hex
notation of a given binary string? (example below)
' '.join('%02x' % ord(b) for b in s)
Oops. Should be:
' '.join(['%02x' % ord(b) for b in s])
The first works fine under Python 2.4, actually... you
need the list comprehension only on previous versions.
-Peter
--
http://mail.python.org/mailman/listinfo/python-list
Re: Fuzzy matching of postal addresses
I think you guys are missing the point. All you would need to add to get a 'probable match' is add another search that goes through the 10% that didnt get matched and do a "endswith" search on the data. From the example data you showed me, that would match a good 90% of the 10%, leaving you with a 1% that must be hand matched. You would have to combine this idea with Jeff Shannon's idea to make it work more efficiently. -- http://mail.python.org/mailman/listinfo/python-list
Re: hex notation funtion
On 2005-01-18, Grant Edwards <[EMAIL PROTECTED]> wrote:
> On 2005-01-18, tertius <[EMAIL PROTECTED]> wrote:
>
>> Is there a builtin function that will enable me to display the hex
>> notation of a given binary string? (example below)
>
> ' '.join('%02x' % ord(b) for b in s)
Oops. Should be:
' '.join(['%02x' % ord(b) for b in s])
--
Grant Edwards grante Yow! .. Am I in a SOAP
at OPERA??
visi.com
--
http://mail.python.org/mailman/listinfo/python-list
Re: pickling extension class
On 18.01.2005, at 20:31, Alex Martelli wrote:
harold fellermann <[EMAIL PROTECTED]> wrote:
File "/sw/lib/python2.4/pickle.py", line 760, in save_global
raise PicklingError(
pickle.PicklingError: Can't pickle : it's
not found as hyper.PeriodicGrid
dir(hyper)
['Dir', 'Neighbors', 'PeriodicGrid', 'PeriodicPos', '__doc__',
'__file__', '__name__', 'refcount']
hyper.PeriodicGrid
So pickle complains about the class PeriodicGrid not being found in
the
module hyper, but a dir()
proves that python can find it. Has anyone an idea what's going wrong
here?
These symptomps are pretty weird -- let's try to pin things down a bit
more. The relevant few lines of pickle.py are:
try:
__import__(module)
mod = sys.modules[module]
klass = getattr(mod, name)
except (ImportError, KeyError, AttributeError):
raise PicklingError(
so, could you please edit your pickle.py to provide VASTLY more info,
[...]
and let us know exactly what his modified pickle.py outputs...?
Here it goes...:
OOPS, error (exceptions.ImportError): No module named hyper
Traceback (most recent call last):
File "pickle_test.py", line 5, in ?
pickle.dump(g,file("test","w"))
File "/Volumes/space/Users/harold/uni/pace/ono/pickle.py", line 1387,
in dump
Pickler(file, protocol, bin).dump(obj)
File "/Volumes/space/Users/harold/uni/pace/ono/pickle.py", line 231,
in dump
self.save(obj)
File "/Volumes/space/Users/harold/uni/pace/ono/pickle.py", line 338,
in save
self.save_reduce(obj=obj, *rv)
File "/Volumes/space/Users/harold/uni/pace/ono/pickle.py", line 414,
in save_reduce
save(func)
File "/Volumes/space/Users/harold/uni/pace/ono/pickle.py", line 293,
in save
f(self, obj) # Call unbound method with explicit self
File "/Volumes/space/Users/harold/uni/pace/ono/pickle.py", line 765,
in save_global
raise PicklingError(
pickle.PicklingError: Can't pickle : it's
not found as hyper.PeriodicGrid
I have noticed that the error does not occur, when the imported module
('hyper') is in the same directory as the script that pickles. When it
is imported from a subpackage (like in the code
I sent you) it goes wrong.
- harold -
--
Reality is for people who lack imagination.
--
http://mail.python.org/mailman/listinfo/python-list
Re: pickling extension class
harold fellermann <[EMAIL PROTECTED]> wrote: >File "/sw/lib/python2.4/pickle.py", line 760, in save_global > raise PicklingError( > pickle.PicklingError: Can't pickle : it's > not found as hyper.PeriodicGrid > >>> dir(hyper) > ['Dir', 'Neighbors', 'PeriodicGrid', 'PeriodicPos', '__doc__', > '__file__', '__name__', 'refcount'] > >>> hyper.PeriodicGrid > > > So pickle complains about the class PeriodicGrid not being found in the > module hyper, but a dir() > proves that python can find it. Has anyone an idea what's going wrong > here? These symptomps are pretty weird -- let's try to pin things down a bit more. The relevant few lines of pickle.py are: try: __import__(module) mod = sys.modules[module] klass = getattr(mod, name) except (ImportError, KeyError, AttributeError): raise PicklingError( so, could you please edit your pickle.py to provide VASTLY more info, say: try: print 'Here it goes...:' _xx = __import__(module) print ' __import__ says: %r' % (_xx,) mod = sys.modules[module] print ' in sys.modules: %r' % (mod,) klass = getattr(mod, name) print ' klass is: %r' % (klass,) except (ImportError, KeyError, AttributeError), _xx: print ' OOPS, error (%s): %s' % (_xx.__class__, _xx) raise PicklingError( and let us know exactly what his modified pickle.py outputs...? Thanks, Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: hex notation funtion
On 2005-01-18, tertius <[EMAIL PROTECTED]> wrote:
> Is there a builtin function that will enable me to display the hex
> notation of a given binary string? (example below)
' '.join('%02x' % ord(b) for b in s)
--
Grant Edwards grante Yow! This is a NO-FRILLS
at flight -- hold th' CANADIAN
visi.comBACON!!
--
http://mail.python.org/mailman/listinfo/python-list
Re: hex notation funtion
This will do it:
>>> int('1000', 2)
128
>>> hex(int('1000', 2))
'0x80'
>>>
--
http://mail.python.org/mailman/listinfo/python-list
Re: How to prevent the script from stopping before it should
Fredrik Lundh wrote: > Steve Holden wrote: > > > You will need to import the socket module and then call socket.setdefaulttimeout() to ensure that > > communication with non-responsive servers results in a socket exception that you can trap. > > or you can use asynchronous sockets, so your program can keep processing > the sites that do respond at once while it's waiting for the ones that don't. for > one way to do that, see "Using HTTP to Download Files" here: > > http://effbot.org/zone/effnews-1.htm > > (make sure you read the second and third article as well) > Dear Fredrik Lundh, Thank you for the link. I checked it. But I have not found an answer to my question. My problem is that I can not finish( sometimes) to download all pages. Sometimes my script freezes and I can not do nothing but restart the script from the last successfully downloaded web page. There is no error saying that was an error. I do not know why; maybe the server is programed to reduce the numbers of connection or there maybe different reasons.So, my idea was two threads. One master ,suprevising the slave thread that would do downloading and if the slave thread stopped, master thread would start another slave. Is it a good solution? Or is there a better solution? Thanks for help Lad -- http://mail.python.org/mailman/listinfo/python-list
Re: how to find site-packages path (Michael Hoffman) - use distutils
I actually target Unix and windows so pyexe won't cut it I'm afraid - same issue with Inno. As far as the site-package target, I don't fully understand your relunctancy. Just as my potential users might not own a compiler, they might not be computer proficient enough to easily understand how to change the sys.path. So until I have found a clean cross platform solution I'm going to have to stick to site-packages. Best regards, Philippe -- *** Philippe C. Martin SnakeCard LLC www.snakecard.com *** -- http://mail.python.org/mailman/listinfo/python-list
Re: how to find site-packages path (Michael Hoffman) - use distutils
Philippe C. Martin wrote: Why would you want to copy any *.pyc instead of compiling them on site? I know that sounds terrible to the open source community, but I do not intend to release the source code for my product That's not why I asked. I'll leave the politics up to you. The thing is, that the path info gets cached in the *.pyc file. This may lead to confusing tracebacks - might they occur - when the user does not install to the exact same drive/path as you did. Additionally: if you *do* want to distribute *.pyc only, I personally wouldn't find it terribly neat if you stuck those into the site-packages directory of my Python installation. I - for one - would want to know what kind of source code you place along *my* sys.path. Maybe you should consider using py2exe to distribute - keeping your *.pyc out of the user's Python directory tree, if any, entirely. Also, you may want to consider using Inno Setup as deployment tool (if Windows is your target platform). Using distutils for a *.py-less installer seems pretty pointless. Regards, -- Vincent Wehren - pls go to philippecmartin.com/applications.html for my _small_ contributions :-)) Regards, Philippe -- http://mail.python.org/mailman/listinfo/python-list
Re: Print to Windows default Printer
Thanks for he quick response. This is small sample code from a PSP script to get Exit Info of a digital image. I want to print to the printer rather than the screen. --- Info = App.Do( Environment, 'ReturnImageInfo' ) print print 'Input Device Information' for key in InputDeviceKeys: if OnlyExistingData == 0 or Info[key] != '': print key, ': ', Info[key] print print 'Artist Information' for key in ArtistKeys: if OnlyExistingData == 0 or Info[key] != '': print key, ': ', Info[key] print -- Is there an easy way to do it. Right now I copy and paste to a txt file then print the file? S "Peter Hansen" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Samantha wrote: >> I am new to Python and I am having considerable trouble trying to print >> (using a simple script) to the default printer rather than the screen. >> Thanks for any help. > > Please show some example code, and explain in more detail > what you are trying to do. There are perhaps *dozens* > of different ways to do printing under Windows, and we > can't guess which approach you are trying, nor which > might be suitable for your needs. > > -Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: hex notation funtion
Would that do it? for i in my_byte_string: = atoi(binascii.hexlify(i),16) Regards, Philippe On Tue, 18 Jan 2005 20:43:44 +0200, tertius wrote: > Hi, > > Is there a builtin function that will enable me to display the hex > notation of a given binary string? (example below) > > many thanks > Tertius > > > > () 02 11 00 00 46 5A 1A 82 02 11 00 39 36 39 33 39 > FZ.96939 > > 0016(0010) 36 39 33 00 0A 30 33 37 34 34 39 35 38 25 DD 01 > 693..03744958%.. -- http://mail.python.org/mailman/listinfo/python-list
Re: hex notation funtion
tertius wrote:
Hi,
Is there a builtin function that will enable me to display the hex
notation of a given binary string? (example below)
Does this help:
>>> "hello".encode("hex")
'68656c6c6f'
>>> "deadbeef".decode("hex")
'\xde\xad\xbe\xef'
?
--Irmen
--
http://mail.python.org/mailman/listinfo/python-list
pickling extension class
Hi all,
I have a problem pickling an extension class. As written in the
Extending/Embedding Manual, I
provided a function __reduce__ that returns the appropreate tuple. This
seams to work fine,
but I still cannot pickle because of the following error:
>>> from model import hyper
>>> g = hyper.PeriodicGrid(4,4,1)
>>> g.__reduce__()
(,(4.,4.,1.))
>>> import pickle
>>> pickle.dump(g,file("test","w"))
Traceback (most recent call last):
File "pickle_test.py", line 5, in ?
pickle.dump(g,file("test","w"))
File "/sw/lib/python2.4/pickle.py", line 1382, in dump
Pickler(file, protocol, bin).dump(obj)
File "/sw/lib/python2.4/pickle.py", line 231, in dump
self.save(obj)
File "/sw/lib/python2.4/pickle.py", line 338, in save
self.save_reduce(obj=obj, *rv)
File "/sw/lib/python2.4/pickle.py", line 414, in save_reduce
save(func)
File "/sw/lib/python2.4/pickle.py", line 293, in save
f(self, obj) # Call unbound method with explicit self
File "/sw/lib/python2.4/pickle.py", line 760, in save_global
raise PicklingError(
pickle.PicklingError: Can't pickle : it's
not found as hyper.PeriodicGrid
>>> dir(hyper)
['Dir', 'Neighbors', 'PeriodicGrid', 'PeriodicPos', '__doc__',
'__file__', '__name__', 'refcount']
>>> hyper.PeriodicGrid
So pickle complains about the class PeriodicGrid not being found in the
module hyper, but a dir()
proves that python can find it. Has anyone an idea what's going wrong
here?
Any help appreceated,
- harold -
--
What is mind? -- Doesn't matter.
What is matter? -- Never mind!
--
--
http://mail.python.org/mailman/listinfo/python-list
hex notation funtion
Hi, Is there a builtin function that will enable me to display the hex notation of a given binary string? (example below) many thanks Tertius () 02 11 00 00 46 5A 1A 82 02 11 00 39 36 39 33 39 FZ.96939 0016(0010) 36 39 33 00 0A 30 33 37 34 34 39 35 38 25 DD 01 693..03744958%.. -- http://mail.python.org/mailman/listinfo/python-list
Re: Print to Windows default Printer
Samantha wrote: I am new to Python and I am having considerable trouble trying to print (using a simple script) to the default printer rather than the screen. Thanks for any help. Please show some example code, and explain in more detail what you are trying to do. There are perhaps *dozens* of different ways to do printing under Windows, and we can't guess which approach you are trying, nor which might be suitable for your needs. -Peter -- http://mail.python.org/mailman/listinfo/python-list
Print to Windows default Printer
I am new to Python and I am having considerable trouble trying to print (using a simple script) to the default printer rather than the screen. Thanks for any help. S -- http://mail.python.org/mailman/listinfo/python-list
Re: One-Shot Property?
On Tue, Jan 18, 2005 at 04:54:56PM +, Kevin Smith wrote: > > I have many cases in my code where I use a property for calculating a > value on-demand. Quite a few of these only need to be called once. > After that the value is always the same. In these properties, I set a > variable in the instance as a cached value and return that value on > subsequent calls. It would be nice if there was a descriptor that would > do this automatically. Actually, what would be really nice is if I > could replace the property altogether and put the calculated value in > its place after the first call, but the property itself prevents me from > doing that. Is this possible? consider this: 1 >>> class C: 2 ... x = property(str) 3 ... 4 >>> c = C() 5 >>> c.x 6 '<__main__.C instance at 0x4008d92c>' 7 >>> setattr(c, 'x', c.x) 8 >>> c.x 9 '<__main__.C instance at 0x4008d92c>' 10 >>> C.x 11 12 >>> c.x = 2 13 >>> in line 5 you see that the x property so defined works. In line 7 you remove it, replacing it with the computed value of the property. Line 9 shows that it worked, line 11 shows that it didn't break the class, and line 13 (through the absence of an exception) shows that it no longer is 'special' (as it shouldn't be). -- John Lenton ([EMAIL PROTECTED]) -- Random fortune: You can tune a piano, but you can't tuna fish. You can tune a filesystem, but you can't tuna fish. -- from the tunefs(8) man page signature.asc Description: Digital signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Integration with java (Jpype vs. JPE)
Joachim Boomberschloss wrote: Option iii would also enable writing independent packages in Python and Java, but its glue layer will be distributed between Python and Java using Jython and Pyro (I chose Pyro because it works in both CPython and Jython, and can be used to communicate between them). Please note that currently it is not possible to use Pyro as a server in Jython. Only as a client. Also; last time I checked there were some bugs in the Jython compiler that were triggered by Pyro's code (parts of it would give a compile error). See http://www.razorvine.net/python/PyroAndJython --Irmen -- http://mail.python.org/mailman/listinfo/python-list
Re: One-Shot Property?
Kevin Smith wrote:
I have many cases in my code where I use a property for calculating a
value on-demand. Quite a few of these only need to be called once.
After that the value is always the same. In these properties, I set a
variable in the instance as a cached value and return that value on
subsequent calls. It would be nice if there was a descriptor that would
do this automatically. Actually, what would be really nice is if I
could replace the property altogether and put the calculated value in
its place after the first call, but the property itself prevents me from
doing that.
This should do it:
class CachingProperty(object):
def __init__(self, attr_name, calculate_function):
self._name = attr_name
self._calculate = calculate_function
def __get__(self, obj, type=None):
if obj is None:
return self
else:
value = self._calculate(obj)
setattr(obj, self._name, value)
return value
And example code:
>>> class Foo(object):
... def calculate_value(self):
... print 'Calculating...'
... return 42
... foo = CachingProperty('foo', calculate_value)
...
>>> bar = Foo()
>>> bar.__dict__
{}
>>> bar.foo
Calculating...
42
>>> bar.foo # Notice that the print statement doesn't run this time
42
>>> bar.__dict__
{'foo': 42}
--
http://mail.python.org/mailman/listinfo/python-list
Re: ANNOUNCE: Altova ... blah blah blah
Altova Announcements wrote: Altova Unveils . [spam] Well now, I didn't like their products very much already, but this spam has certainly made them drop another few steps down on my scale. Hmpf. --Irmen -- http://mail.python.org/mailman/listinfo/python-list
Re: generator expressions: performance anomaly?
On Tue, 18 Jan 2005 14:05:15 +, Antoon Pardon wrote: > I don't see how generating byte code for a = 9; when seeing the > expression a = 3 + 6, would be a problem for non-functional > languages. To answer nearly every post you've made to this thread, "because Python doesn't have the resources to program to special cases". And as is often the case in this sort of discussion, sure, adding this might be only a little work, but there's thousands of enhancements of the same general work level and performance gain. So remember you're not just espousing this particular enhancement, you're implicitly arguing for the entire class (because there is nothing to discriminate in the argument "this is fairly easy" between this particular feature on your mind today and the other thousands of such features). To address your point more specifically, you can do this subexpression elimination to the extent that your expression is a purely functional one. "a = 3 + 6", while written in an imperative language and setting a variable in an imperative manner, has a "functional subexpression" "3 + 6", that has no side-effects, etc., so the compiler could reduce it if it knew how. (In Python, that's a function call, but since you can't change __add__ on ints, you could do this, although there's still some special casing you're doing that will ripple unpleasantly through the code.) But as soon as you call any sort of method or function, you're done. Ultimately, the use is fairly limited; I can't imagine the execution time saved would reach the time of implementation for weeks after a release, even aggregating across all Python use in the world, and "real time gained" (i.e., time useful to a human) would probably never add up to the implementation time. So why bother? That's a horrid trade off when there are so many other real gains to be had. -- http://mail.python.org/mailman/listinfo/python-list
Re: One-Shot Property?
Kevin Smith wrote: I have many cases in my code where I use a property for calculating a value on-demand. Quite a few of these only need to be called once. After that the value is always the same. In these properties, I set a variable in the instance as a cached value and return that value on subsequent calls. It would be nice if there was a descriptor that would do this automatically. Actually, what would be really nice is if I could replace the property altogether and put the calculated value in its place after the first call, but the property itself prevents me from doing that. Is this possible? If you use the old-fashioned __getattr__ method instead of properties. __getattr__ gets called only if the value can't be found in the instance dictionary. def __getattr__ (self, attrname): try: method = getattr (self, 'calculate_' + attrname) except AttributeError: raise AttributeError, attrname value = method () setattr (self, attrname, value) return value And probably also through metaclasses. And decorators. Daniel -- http://mail.python.org/mailman/listinfo/python-list
Re: script to automate GUI application (newbie)
It sounds like a case for the Expect program, to me. Try Google-ing for "Expect". If you are looking for a Python approach, then try googling for "Expect Python". Jim -- http://mail.python.org/mailman/listinfo/python-list
Re: One-Shot Property?
Kevin Smith wrote: I have many cases in my code where I use a property for calculating a value on-demand. Quite a few of these only need to be called once. After that the value is always the same. In these properties, I set a variable in the instance as a cached value and return that value on subsequent calls. It would be nice if there was a descriptor that would do this automatically. Actually, what would be really nice is if I could replace the property altogether and put the calculated value in its place after the first call, but the property itself prevents me from doing that. Is this possible? I was going to recommend taking a look at the "memoize" example on the Python wiki, but it seems to be missing at the moment. In any case, here's the URL: http://www.python.org/moin/PythonDecoratorLibrary There are also a few examples on the Cookbook, like this one: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/325205 It shouldn't be too difficult to adapt this technique so that it can be used to create properties. I wouldn't bother replacing the property with an attribute unless you have a specific reason to do so (performance, perhaps). HTH, Dave -- http://mail.python.org/mailman/listinfo/python-list
Re: simultaneous multiple requests to very simple database
Robert Brewer wrote: Eric S. Johansson wrote: I have an application where I need a very simple database, effectively a very large dictionary. The very large dictionary must be accessed from multiple processes simultaneously. I need to be able to lock records within the very large dictionary when records are written to. Just to clarify, you want shared-read until a write, at which point you want to lock just the item being written? Or would page or table locking be acceptable at that point? just the item/record. I'm doing arrival rate calculations. each record contains a set of arrival times and I am rewriting the record every time a new entry arrives. complete page or table locking will work in the sense that it will prevent collisions but it will have an increasing impact as load and simultaneous table but not record accesses increase. ---eric -- http://mail.python.org/mailman/listinfo/python-list
Re: [perl-python] 20050118 keyed list
Jürgen Exner wrote: >> © # see "perldoc perldata" for an unix-styled course. > > Excuse me? Do you mind explaining where exactly perldata is "Unix-styled"? Remember: Perl == Unix == Satan. Reinhold -- http://mail.python.org/mailman/listinfo/python-list
