Re: Getting not derived members of a class
On 'y', Python has no way of recording where '_a' and '_b' were set, so
you can't tell whether it comes from class 'a' or 'b'.
You can find the attributes that are defined on 'b' only, though, by
using 'b.__dict__.keys()', or 'y.__class__.__dict__.__keys__()'. This
gives
['__module__', 'who1', '__init__', '__doc__']
If you want to limit yourself to current versions of cpython (because the
bytecode used in cpython is only an implementation detail) and define a 'member
of class a' as one where a.__init__ has a statement like 'self.z = ...', you
can peer into the bytecodes. Something like this:
from dis import HAVE_ARGUMENT, opname
LOAD_FAST = chr(opname.index('LOAD_FAST'))
STORE_ATTR = chr(opname.index('STORE_ATTR'))
HAVE_ARGUMENT = chr(HAVE_ARGUMENT)
def find(cls):
ns = cls.__dict__
result = ns.keys()
init = ns.get('__init__', None)
if not init: return ns
f = ns['__init__'].func_code.co_code
n = ns['__init__'].func_code.co_names
i = 0
while i < len(f) - 6:
if (f[i] == LOAD_FAST and f[i+1] == f[i+2] == '\0'
and f[i+3] == STORE_ATTR):
j = ord(f[i+4]) + 256 * ord(f[i+5])
result.append(n[j])
i += 6
elif f[i] > HAVE_ARGUMENT:
i += 3
else:
i += 1
return result
>>> import franz
>>> franz.find(y.__class__)
['__module__', 'who1', '__init__', '__doc__', '_b']
Jeff
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Re: Newb: Telnet 'cooked data','EOF' queries.
On Sun, Jul 31, 2005 at 01:30:43PM +0100, glen wrote: > Could someone explain what "cooked data" is. The telnet protocol contains special sequences which are interpreted by the telnet client or server program. These are discussed in the telnet RFC, which is RFC854 according to the telnetlib docstring. "Cooked" data is data after these special sequences are removed. > Also when trying read_all() the program seems to lock up, which I assume > is because it is waiting for an EOF, but 'when' is an EOF received. As far as I know, the only EOF in telnet is when the other side closes the socket. Jeff pgpnCbDvhyN27.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: A replacement for lambda
On Fri, Jul 29, 2005 at 10:14:12PM -0700, Tim Roberts wrote: > C++ solves this exact problem quite reasonably by having a greedy > tokenizer. Thus, that would always be a left shift operator. To make it > less than and a function, insert a space: > < Incidentally, I read in an article by Bjarne Stroustrup[1] that "C++0x" will parse vector> v; just like today's compilers parse vector > v; Another of the changes he discusses, letting 'auto i = ...' create i with the type of the expression '...', will certainly be an improvement. Even better if the keyword 'auto' could be made optional! (Of course, this is another break with C, where the declaration auto i; makes 'i' an int) And what's this got to do with Python? I dunno. Sorry. Jeff [1] http://www.informit.com/content/images/art_stroustrup_2005/elementLinks/rules.pdf pgpmO2bTojrLg.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: poplib.POP3.list() returns extra value?
With a judicious bit of UTSL, that count seems to be the total number of octets in the reply. This information comes from any user of _getlongresp(), which actually returns a tuple (resp, list, octets). These methods would be: list retr top uidl I'd consider it a doc bug too. If you feel comfortable doing it, dive in and improve the documentation of poplib. Submitting a patch to the patch tracker on sf.net/projects/python is probably the best way to do this, if you have the necessary knowledge of cvs to produce a patch. Jeff pgpR6zOckMUPS.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: codecs.getencoder encodes entire string ?
On Thu, Jul 28, 2005 at 08:42:57AM -0700, nicolas_riesch wrote: > And a last question: can I call this "enc" function from multiple > threads ? Yes. Jeff pgphSka1eU9PQ.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Stripping C-style comments using a Python regexp
#
import re, sys
def q(c):
"""Returns a regular expression that matches a region delimited by c,
inside which c may be escaped with a backslash"""
return r"%s(\\.|[^%s])*%s" % (c, c, c)
single_quoted_string = q('"')
double_quoted_string = q("'")
c_comment = r"/\*.*?\*/"
cxx_comment = r"//[^\n]*[\n]"
rx = re.compile("|".join([single_quoted_string, double_quoted_string,
c_comment, cxx_comment]), re.DOTALL)
def replace(x):
x = x.group(0)
if x.startswith("/"): return ' '
return x
result = rx.sub(replace, sys.stdin.read())
sys.stdout.write(result)
#
The regular expression matches ""-strings, ''-character-constants,
c-comments, and c++-comments. The replace function returns ' ' (space)
when the matched thing was a comment, or the original thing otherwise.
Depending on your use for this code, replace() should return as many
'\n's as are in the matched thing, or ' ' otherwise, so that line
numbers remain unchanged.
Basically, the regular expression is a tokenizer, and replace() chooses
what to do with each recognized token. Things not recognized as tokens
by the regular expression are left unchanged.
Jeff
PS this is the test file I used:
/* ... */ xyzzy;
456 // 123
const char *mystr = "This is /*trouble*/";
/* * */
/* /* */
// /* /* */
/* // /* */
/*
* */
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Re: Tkinter - Resizing a canvas with a window
You should just use 'pack' properly. Namely, the fill= and expand= parameters. In this case, you want to pack(fill=BOTH, expand=YES). For the button, you may want to use pack(anchor=E) or anchor=W to make it stick to one side of the window. The additional parameters for the button (both creation and packing) give a geometry that is closer to the standard buttons in Windows 95 / Windows 2000. Use those or not, as you see fit. Here's the new program: from Tkinter import * class testApp2: def __init__( self, master ): self.ma = master self.f = Frame( self.ma ) self.f.pack(fill=BOTH, expand=YES) self.cv = Canvas(self.f, width=25, height=25, bg='red') self.cv.pack(fill=BOTH, expand=YES) self.b1 = Button( self.f, text='Hello', height=1, width=10, padx=0, pady=1) self.b1.pack(side=BOTTOM, anchor=E, padx=4, pady=4) root = Tk() app = testApp2(root) root.mainloop() Jeff PS thanks for including a full, runnable program in your post! pgpqy4uUUgiLH.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: How to realize ssh & scp in Python
Rather than doing anything with passwords, you should instead use public key authentication. This involves creating a keypair with ssh_keygen, putting the private key on the machine opening the ssh connection (~/.ssh/id_rsa), then listing the public key in the remote system's ~/.ssh/authorized_keys. If you don't want to use this approach, `pexpect'[1] is supposed to be able to perform this sort of tasks, and one of its examples is called `sshls.py'. I just downloaded it, and after changing the ssh commandline to include -o 'PreferredAuthentications password' it worked for me. In another recent thread, a different poster claimed it didn't work, so your results may vary. Jeff [1] http://pexpect.sourceforge.net/ pgprScaQubqXA.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about namespaces and import. How to avoid calling os.system
In main.py, execfile("gen.py")
or
In gen.py, have something like
from __main__ import env_params
or
In main.py, have something like
import __builtins__; __builtins__.env_params = env_params
or
call a function in the gen.py with env_params as a parameter
import gen
gen.do(env_params)
Jeff
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Re: Getting TypeError in Changing file permissions
If you are using Unix, and all you have is the file object, you can use os.fchmod(outfile.fileno(), 0700) Jeff pgp8U05e26RUt.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Mapping a drive to a network path
in fact, see this thread, it may have something useful for you: http://mail.python.org/pipermail/python-win32/2003-April/000959.html Jeff pgprYPOH3yOyI.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Mapping a drive to a network path
import os os.system(r"net use z: \\computer\folder") Something in the win32net module of win32all may be relevant if you don't want to do it through os.system: http://aspn.activestate.com/ASPN/docs/ActivePython/2.4/pywin32/win32net__NetUseAdd_meth.html Jeff pgp7mEoPdAfNP.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: time.time() under load between two machines
What makes you believe that the two machines' clocks are perfectly
synchronized? If they're not, it easily explains the result.
I wrote a simple client/server program similar to what you described.
Running on two RedHat 9 machines on a local network, I generally
observed a time delta of 2ms (compared to typical 0.17ms latency
reported by "ping"), never in a negative direction. These machines
times are synchronized by ntpd from the package ntp-4.1.2-0.rc1.2.
My program can be run like this:
rsh otherhost python timely.py -s | python timely.py -r
the values printed are the difference between the remote time before the
message is sent and the local time after the message is received.
You mention using Windows. I don't know whether Windows machines by
default use anything as sophisticated as ntpd to keep their clocks
accurate.
Whatever is going on in your case, I suspect it is the operating system,
not Python.
Jeff
import os, sys, time
def serve():
while 1:
data = struct.pack("!d", time.time())
os.write(1, data)
time.sleep(1)
def recv(fileno):
while 1:
data = struct.unpack("!d", os.read(fileno, 8))[0]
now = time.time()
print now - data
if sys.argv[1] == "-s":
serve()
else:
recv(0)
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Re: Filling up commands.getstatusoutput's buffer
On Wed, Jul 20, 2005 at 03:10:49PM -0700, [EMAIL PROTECTED] wrote:
> Hey,
>
> Has anyone ever had commands.getstatusoutput's buffer fill up when
> executing a verbose command? [...]
How much output are you talking about? I tried outputs as large as
about 260 megabytes without any problem. (RedHat 9, Python 2.2)
>>> len(commands.getoutput("dd if=/dev/zero bs=512 count=512000 2>/dev/null"))
262144000
>>> 512 * 512000
262144000
Jeff
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Re: Image orientation and color information with PIL?
On Mon, Jul 18, 2005 at 10:55:42AM -0600, Ivan Van Laningham wrote: > How are you going to determine the orientation of an image without > sophisticated image analysis? There is research on automatic image > orientation detection. [...] > If you write it I'll use it;-) There's research going on in this area. Here are a few papers: http://www.dcs.shef.ac.uk/teaching/eproj/msc2004/abs/m3zs2.htm http://research.microsoft.com/research/pubs/view.aspx?pubid=918 there are probably many others. I considered implementing one of these algorithms back in 2003 or so, but instead I bought a digital camera with an orientation sensor. Jeff pgpJZsejWH68l.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Image orientation and color information with PIL?
>>> i = Image.open("blue.jpg")
>>> i.size
(3008, 2000)
>>> i.mode
'RGB'
'RGB' is the value for color jpeg images. I believe that for black&white
images, i.mode is 'L' (luminosity).
If you want to determine whether an existing image is landscape or portrait,
then just compare i.size[0] (width) and i.size[1] (height).
If by "determine if an image is horizontal/vertical", you want to find
the orientation data recorded by some digital cameras, you can do that
with PIL 1.1.4. According to the release notes for 1.1.4,
+ Added experimental EXIF support for JPEG files. To extract EXIF
information from a JPEG file, open the file as usual, and call the
"_getexif" method. If successful, this method returns a dictionary
mapping EXIF TIFF tags to values. If the file does not contain EXIF
data, the "_getexif" method returns None.
The "ExifTags" module contains a dictionary mapping tags to tag
names.
This interface will most likely change in future versions.
The exif tag 274 is Orientation. The values you'll see most often are 1
(Normal), 6 and 8 (90 and 270 degree rotations). Orientation can also encode
180 degree rotation, as well as any of the four rotations combined with a
mirror operation.
>>> [k for (k,v) in ExifTags.TAGS.items() if v == 'Orientation']
[274]
>>> e = i._getexif()
>>> if e: print e[274]
1
I have written a standalone Python module that reads and changes the EXIF
orientation data. You can view it here:
http://unpy.net/cgi-bin/viewcvs.cgi/aethertool/disorient.py?rev=1.2&content-type=text/vnd.viewcvs-markup
It is available under the terms of the GNU GPL.
Here's another page about EXIF orientation data:
http://sylvana.net/jpegcrop/exif_orientation.html
Jeff
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Re: Opinions on KYLIX 3 (Delphi 4 Linux)
I honestly don't know why anyone would spend money for a development environment, no matter how fancy. I don't know why anyone would develop software in a language that doesn't have at least one open implementation. It's a great way to get screwed when Borland goes under or decides they only want to sell a new, incompatible product. What do you do with your existing product when that happens? Re-train on a new platform, and re-write from scratch? Just say no to proprietary software. Jeff pgpiV5WmgG2I1.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows command line problem
I don't exactly know what is going on, but '\x96' is the encoding for
u'\N{en dash}' (a character that looks like the ASCII dash,
u'\N{hyphen-minus}', u'\x45') in the following windows code pages:
cp1250 cp1251 cp1252 cp1253 cp1254
cp1255 cp1256 cp1257 cp1258 cp874
Windows is clearly doing something clever.
Jeff
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Re: stdin/stdout fileno() always returning -1 from windows service
It seems to simply be common wisdom. e.g., http://mail.python.org/pipermail/python-win32/2004-September/002332.html http://mail.mems-exchange.org/pipermail/quixote-users/2004-March/002743.html http://twistedmatrix.com/pipermail/twisted-python/2001-December/000644.html etc If you can find chapter and verse on MSDN, more power to you. This page implies that the "standard handles" are only available when there is a console for the application. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/getstdhandle.asp Jeff pgpD1VX32k6bY.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: stdin/stdout fileno() always returning -1 from windows service
On Sun, Jul 17, 2005 at 06:43:00PM -0700, chuck wrote:
> I have found that sys.stdin.fileno() and sys.stdout.fileno() always
> return -1 when executed from within a win32 service written using the
> win32 extensions for Python.
>
> Anyone have experience with this or know why?
because there *is* no standard I/O for a windows service.
You should be able to execute code like
import sys
sys.stdout = sys.stderr = open("some.log", "w")
if you have code that expects the standard output files to be available.
You could also open sys.stdin in a similar way.
Jeff
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Re: ssh popen stalling on password redirect output?
In your ssh configuration, specify something like PreferredAuthentication "hostbased,publickey" this will skip trying to use the methods called keyboard-interactive and password. You can give this flag on the ssh commandline, too. read the ssh(1) and ssh_config(5) manpages for more information. Jeff pgpYxuAq33BRa.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Browser plug-in for Python?
Back in the day there was 'grail', which was a browser in its own right. There may also have been a plug-in for other browsers, but I don't know any real details about them. Python itself has deprecated the 'restricted execution' environment it had in previous versions, because ways to break out of the jail existed or were thought to exist, and nobody stepped forward and offered to spend the requisite time to create and validate (even in a hand-wavy kind of way) a new security model. If you want to write programs in Python and run them in today's browsers, the shortest path from here to there is jython. Several applet demos are available at http://www.jython.org/applets/index.html I have used Jython a little bit, but never seriously and not in the past few years. Jython implements an older version of the Python language, corresponding to cPython 2.1 if I remember correctly. Jeff pgpp6YhsWNcK0.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Parsing Data, Storing into an array, Infinite Backslashes
Your code is needlessly complicated.
Instead of this business
while 1:
try:
i = fetch.next()
except stopIteration:
break
simply write:
for i in fetch:
(if there's an explicit 'fetch = iter(somethingelse)' in code you did
not show, then get rid of that and just loop 'for i in somethingelse')
i[1] will never compare equal to count, because i[1] is always a string
and count is always an integer. Integers and strings are never equal to
each other.
Wring code like
x = "a string " + 3
does not work in Python. You can either convert to a string and then
use the + operator to concatenate:
x = "a string " + str(3)
or you can use %-formatting:
x = "a string %s" % 3
("%s" accepts any sort of object, not just strings)
Using repr(...) (`...` is just a shorthand for this) is what is really
introducing the backslashes. When it outputs a string, it quotes the
string using backslashes. But you pass the old part of the prepared
string through it each time, which leads to doubling backslashes.
Below is a program I wrote to process the data in your message. It prints
out
Memory 2 Summary=0, Speed=PC3200U-30330, Type=DDR SDRAM, Size=512,
Slot=DIMM2/J13, ConfigurationType=2
Memory 3 Summary=0, Speed=PC3200U-30330, Type=DDR SDRAM, Size=512,
Slot=DIMM3/J14, ConfigurationType=2
Memory 0 Summary=0, Speed=PC3200U-30330, Type=DDR SDRAM, Size=512,
Slot=DIMM0/J11, ConfigurationType=2
Memory 1 Summary=0, Speed=PC3200U-30330, Type=DDR SDRAM, Size=512,
Slot=DIMM1/J12, ConfigurationType=2
the result is out of order because the result of calling .items() on a
dict is in an arbitrary order.
Jeff
s = [['Memory', '0', 'Summary', '0'], ['Memory', '0', 'Speed',
'PC3200U-30330'], ['Memory', '0', 'Type', 'DDR SDRAM'], ['Memory', '0',
'Size', '512'], ['Memory', '0', 'Slot', 'DIMM0/J11'], ['Memory', '0',
'ConfigurationType', '2'], ['Memory', '1', 'Summary', '0'], ['Memory',
'1', 'Speed', 'PC3200U-30330'], ['Memory', '1', 'Type', 'DDR SDRAM'],
['Memory', '1', 'Size', '512'], ['Memory', '1', 'Slot', 'DIMM1/J12'],
['Memory', '1', 'ConfigurationType', '2'], ['Memory', '2', 'Summary',
'0'], ['Memory', '2', 'Speed', 'PC3200U-30330'], ['Memory', '2',
'Type', 'DDR SDRAM'], ['Memory', '2', 'Size', '512'], ['Memory', '2',
'Slot', 'DIMM2/J13'], ['Memory', '2', 'ConfigurationType', '2'],
['Memory', '3', 'Summary', '0'], ['Memory', '3', 'Speed',
'PC3200U-30330'], ['Memory', '3', 'Type', 'DDR SDRAM'], ['Memory', '3',
'Size', '512'], ['Memory', '3', 'Slot', 'DIMM3/J14'], ['Memory', '3',
'ConfigurationType', '2']]
query = {}
for a, b, c, d in s:
if not query.has_key((a,b)): query[(a,b)] = []
query[(a,b)].append("%s=%s" % (c, d))
for (a,b), v in query.items():
print a, b, ", ".join(v)
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Re: cursor positioning
Here's a simple module for doing progress reporting. On systems without
curses, it simply uses "\r" to return the cursor to the first column.
On systems with curses, it also clears to the end of the line. This
means that when the progress message gets shorter, there aren't droppings
left from the longer ones.
You have to take care that the progress message isn't wider than the
screen, but I don't know a nice way to *find* the width of the screen
that will work on windows and unix. Hardcoding 80 ain't it either.
import sys
def progress(s):
sys.stderr.write(s + CLEAR_EOL + "\r"); sys.stderr.flush()
try:
import curses
except ImportError:
CLEAR_EOL = ''
else:
curses.setupterm()
CLEAR_EOL = curses.tigetstr("el") or ''
def test():
import time
for j in range(2):
for i in range(100):
progress("Doing item %d, %d%%" % (i * 100, i))
time.sleep(.01)
if __name__ == '__main__': test()
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Re: About undisclosed recipient
You provided far too little information for us to be able to help. If you are using smtplib, it doesn't even look at message's headers to find the recipient list; you must use the rcpt() method to specify each one. If you are using the sendmail method, the "to_addrs" list has no relationship to the headers of the actual message---it simply calls rcpt() once for each address in to_addrs. The example in the docstring doesn't even *have* a To: header in the message! Jeff pgpHNq6sWEuR7.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Query
python-xlib includes an implementation of the xtest extension, which is enabled on most users' X servers, and can be used to send arbitrary keyboard or mouse events. jeff pgpo7pqhBafPe.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Strange os.path.exists() behaviour
Pierre wrote:
> Python 2.4 (#60, Nov 30 2004, 11:49:19) [MSC v.1310 32 bit (Intel)] on win32
^^^
Here's the bug. You're using Windows. It's a filesystem, but not as we know
it...
Anyway, You are getting exactly what the low-level Windows APIs return.
Here's a small "C" program. It prints "0" next to the filename if the
file exists, -1 otherwise, as described at
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclib/html/_crt__access.2c_._waccess.asp
int main(int argc, char **argv) {
int i;
for(i=1; idir
Volume in drive C has no label.
Volume Serial Number is 171D-4D2A
Directory of C:\TMP\example
07/06/05 03:04p .
07/06/05 03:04p ..
07/06/05 03:05p 3 exist
3 File(s) 3 bytes
C:\TMP\example>x:a.exe exist exist. exist nonexist nonexist. nonexist...
exist: 0
exist.: 0
exist: 0
nonexist: -1
nonexist.: -1
nonexist...: -1
C:\TMP\example>type nonexist
The system cannot find the file specified.
C:\TMP\example>type exist
C:\TMP\example>
As you can see, not only does Windows think that "exist" exists, but it can
successfully "type" its contents too!
Jeff
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Re: math.nroot [was Re: A brief question.]
On Tue, Jul 05, 2005 at 09:49:33PM +0100, Tom Anderson wrote: > Are there any uses for NaN that aren't met by exceptions? Sure. If you can naturally calculate two things at once, but one might turn out to be a NaN under current rules. x, y = calculate_two_things() if isnan(x): perform_next_step_with_only_y(y) else: perform_next_step_with_both(x, y) Under your scheme, you'd have to write try: x, y = calculate_two_things() except NaNException: y = calculate_one_thing() perform_next_step_with_only_y(y) else: perform_next_step_with_both(x, y) and at the very least duplicate the code for calculating 'y', possibly re-doing a lot of work at runtime too. Jeff pgpVUpJh4xufX.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: resume upload
probably by using REST. This stupid program puts a 200 line file by
sending 100 lines, then using REST to set a resume position and sending
the next 100 lines.
import getpass, StringIO, ftplib
lines = ["Line %d\n" % i for i in range(200)]
part1 = "".join(lines[:100])
part2 = "".join(lines[:100])
f = ftplib.FTP('server', 'username', 'password')
f.debugging = True
f.sendcmd('CWD /tmp')
f.storbinary("STOR example", StringIO.StringIO(part1))
f.putcmd('REST %d' % len(part1))
resp = f.getresp();
if resp[0] != '3': raise ftplib.error_reply, resp
f.storbinary("STOR example", StringIO.StringIO(part2))
f.quit()
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Re: Tkinter + Tcl help
I think you need to write
root.tk.eval('load', '...\\libtcldot.so.0')
When you write
root.tk.eval("x y z")
it's like doing this at the wish/tclsh prompt:
# {x y z}
Not like this:
# x y z
Now, how useful it is to have a command called "x y z", I can't
guess... but tcl would let you do it.
I've also doubled the backslash in your library filename. When using
windows-style paths in string literals, you must either double the
backslashes, or use r'' strings. When you don't, it will often work,
but if the character after the un-doubled backslash is one with special
meaning (including the commonly-seen \r and \t, but also other letters)
then you'll get a pathname and an error that leave you scratching your
head.
Jeff
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Re: importing pyc from memory?
This stupid code works for modules, but not for packages. It probably has bugs.
import marshal, types
class StringImporter:
def __init__(self, old_import, modules):
self._import = old_import
self._modules = modules
def __call__(self, name, *args):
module = self._modules.get(name, None)
if module is None:
return self._import(name, *args)
code = marshal.loads(module)
mod = types.ModuleType(name)
exec code in mod.__dict__
return mod
def test():
import __builtin__
__builtin__.__import__ = StringImporter(__builtin__.__import__,
{ 'test_importer': open("/usr/lib/python2.3/os.pyc").read()[8:] })
import test_importer
print test_importer.path.join("a", "b")
print test_importer.__doc__
if __name__ == '__main__': test()
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Re: Trapping user logins in python ( post #1)
I don't know of a portable way for an inetd-style daemon to "listen" for user logins. On some systems (including RedHat/Fedora and debian), you may be able to use PAM to do this. (pam modules don't just perform authentication, they can take other actions. As an example, pam_lastlog "prints the last login on successful login". I'm not sure what priviledge a pam module has when it executes. A more standard way to do this would be to place lines in /etc/profile /etc/csh.login and so forth for any other shells used on your system. RedHat-style systems have an /etc/profile.d where you can drop a file that will be executed at login, too. This will, of course, be executed with the user's privilege level. Another problem with this approach is that /etc/profile is executed for a "login shell", but a graphical login is not a login shell. Jeff pgpaiKK6vpl7N.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: It seems that ZipFile().write() can only write files, how can empty directories be put into it?
This has been discussed before. One thread I found was http://mail.python.org/pipermail/python-list/2003-June/170526.html The advice in that message might work for you. Jeff pgpPSqdIxsPgx.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Dictionary to tuple
It looks like you want tuple(d.iteritems())
>>> d = {1: 'one', 2: 'two', 3: 'three'}
>>> tuple(d.iteritems())
((1, 'one'), (2, 'two'), (3, 'three'))
You could also use tuple(d.items()). The result is essentially the
same. Only if the dictionary is extremely large does the difference
matter. (or if you're using an older version of Python without the
iteritems method)
Jeff
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Re: Beginner question: Converting Single-Element tuples to list
On Mon, Jun 27, 2005 at 08:21:41AM -0600, John Roth wrote: > Unfortunately, I've seen that behavior a number of times: > no output is None, one output is the object, more than one > is a list of objects. That forces you to have checks for None > and list types all over the place. maybe you can at least push this into a single convenience function... def destupid(x, constructor=tuple, sequencetypes=(tuple, list)): if x is None: return constructor() if isinstance(x, sequencetypes): return x return constructor((x,)) Jeff pgpC9L79OCj2p.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Frame widget (title and geometry)
Tkinter.Frame instances are not created with "geometry" or "title" attributes. Whatever 'classtitle' and 'classtitle2' are, they are not written to work with Tkinter.Frame instances. Jeff pgppDkXNnBRVL.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Frame widget (title and geometry)
It would help if you posted your code, as we're in the dark about exactly what you tried to do and the error you received. It sounds like you may be using the wrong type of widget for what you want. The terms used in Tk are different than in some other systems. If you want a separate window with title bar etc, you want to create a new instance of Tkinter.Toplevel. It will have methods like wm_title and wm_geometry. Newer versions of Tk (8.4 and maybe 8.3) have a widget called "labelframe" (called Tkinter.LabelFrame in python2.3 and newer) which is the grooved-border-and-label container used to semantically group related widgets. "Frame" widgets are simply containers which are often useful for making the screen layout work the way you want with pack and grid. Jeff pgpdBiMtDJV5v.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Is this a bug? I don't know where to start
Your list "targets" contains some values twice. >>> targets=[97,101,139,41,37,31,29,89,23,19,8,13,131,19,73,97,19,139,79,67,61,17,113,127] >>> for t in set(targets): ... if targets.count(t) > 1: print t ... 97 139 19 It looks like the "duplicated" items in the output contain one of the duplicated items from the input. Jeff pgpqzHdpM3xQ3.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Loop until condition is true
def until(pred): yield None while True: if pred(): break yield None def example(): i = 0 for _ in until(lambda: x==0): x = 10 - i i += 1 print x, i example() pgpeP7iW6mcQm.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: PEP ? os.listdir enhancement
Why not just define the function yourself? Not every 3-line function needs to be built in. def listdir_joined(path): return [os.path.join(path, entry) for entry in os.listdir(path)] dirs = [x for x in listdir_joined(path) if os.path.isdir(x)] path_size = [(x, getsize(x)) for x in listdir_joined(path) if os.path.isfile(x)] Jeff pgpwXvnkgy6r4.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: utf8 silly question
If you want to work with unicode, then write
us = u"\N{COPYRIGHT SIGN} some text"
You can also write this as
us = unichr(169) + u" some text"
When you have a Unicode string, you can convert it to a particular
encoding stored in a byte string with
bs = us.encode("utf-8")
It's generally a mistake to use the .encode() method on a byte string,
but that's what code like
bs = "\xa9 some text"
bs = bs.encode("utf-8")
does. It can lull you into believing it works, if the test data only
has US ASCII contents, then break when you go into production and have
non-ASCII strings.
Jeff
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Re: eval() in python
On Tue, Jun 21, 2005 at 08:13:47AM -0400, Peter Hansen wrote: > Xah Lee wrote: > > the doc seems to suggest that eval is only for expressions... it says > > uses exec for statements, but i don't seem to see a exec function? > > Because it's a statement: http://docs.python.org/ref/exec.html#l2h-563 but the documentation is sooo baaad that it makes babies cry and maybe spreads herpes too. pgpV9sZIg0dFB.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Embedding Python - Deleting a class instance
I wrote the following module to test the behavior of PyInstance_New. I
called it something like this:
import vedel
class k:
def __del__(self): print "deleted"
vedel.g(k)
I get output like:
after creation, x->refcnt = 1
doing decref
deleted
after decref
Unless there's a cycle and GC gets involved, all there is to deleting
*anything* in Python is correctly managing the refcount. On the other
hand, you can never free an object while it is still reachable. Some
local name "x" may never spontaneously lose the thing it refers to.
/**/
#include
static PyObject *g(PyObject *s, PyObject *o) {
PyObject *x = PyInstance_New( o, NULL, NULL);
if(x) {
printf("after creation, x->refcnt = %d\n", x->ob_refcnt);
printf("doing decref\n");
Py_DECREF(x);
printf("after decref\n");
} else {
printf("x == NULL\n");
}
Py_INCREF(Py_None);
return Py_None;
}
static PyMethodDef methods[] = {
{"g", (PyCFunction)g, METH_O, NULL},
{NULL},
};
void initvedel(void) {
Py_InitModule("vedel", methods);
}
/**/
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Re: log in to a website
You may find the third-party modules "ClientForm" and "ClientCookie" to
be useful.
Using ClientForm, the following code uploads a file to a particular web form:
forms = ClientForm.ParseResponse(urllib2.urlopen(url))
f = forms[0]
f.add_file(open(local, "rb"), filename=remote, name="file")
u = f.click("attach")
urllib2.urlopen(u)
A web search should turn up the homepage for these modules.
Jeff
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Re: Programmatic links in a TKinter TextBox
Based on the location where the user clicked, you can find the
associated tags. Then you must loop through them to find the one that
gives the "href" value.
Jeff
:r /tmp/link.py
import Tkinter
app = Tkinter.Tk()
text = Tkinter.Text(app)
text.pack()
def click(event):
#this doesn't work
print event
w = event.widget
x, y = event.x, event.y
tags = w.tag_names("@%d,%d" % (x, y))
for t in tags:
if t.startswith("href:"):
print "clicked href %s" % t[5:]
break
else:
print "clicked without href"
return "break"
def show_hand_cursor(event):
event.widget.configure(cursor="hand1")
def show_arrow_cursor(event):
event.widget.configure(cursor="")
# configure text tag
text.tag_config("a", foreground="blue", underline=1)
text.tag_bind("a", "", show_hand_cursor)
text.tag_bind("a", "", show_arrow_cursor)
text.tag_bind("a", "", click)
text.config(cursor="arrow")
#add text
text.insert(Tkinter.INSERT, "click here!", "a")
text.insert(Tkinter.INSERT, "\n")
#add a link with data
href = "http://www.example.com";
text.insert(Tkinter.END, "this is a ")
text.insert(Tkinter.END, "link", ("a", "href:"+href))
app.mainloop()
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Re: Strange socket problem
When using os.system(), files that are open in the parent are available
in the child, as you can see here in Linux' listing of the files open by
the child program:
[EMAIL PROTECTED] jepler]$ python -c 'f = open("/tmp/test", "w"); print
f.fileno(); import os; os.system("ls -l /proc/self/fd")'
3
total 5
lrwx-- 1 jepler jepler 64 Jun 15 07:25 0 -> /dev/pts/2
lrwx-- 1 jepler jepler 64 Jun 15 07:25 1 -> /dev/pts/2
lrwx-- 1 jepler jepler 64 Jun 15 07:25 2 -> /dev/pts/2
l-wx-- 1 jepler jepler 64 Jun 15 07:25 3 -> /tmp/test
lr-x-- 1 jepler jepler 64 Jun 15 07:25 4 -> /proc/3108/fd
You may be able to set the FD_CLOEXEC flag on the files that should not
be passed to children, something like this:
old = fcntl.fcntl(fd, fcntl.F_GETFD)
fcntl.fcntl(fd, fcntl.F_SETFD, old | fcntl.FD_CLOEXEC)
Refer to a real Unix reference for more information on what FD_CLOEXEC
does.
You may want to replace the use of os.system() with fork + close files
+ exec. Then "myserver.py" will no longer have the listening socket
descriptor of your cherrypy server.
Python 2.4's 'subprocess' module may work better in this respect than
os.system. It seems to include support for requesting that fds be
closed in the child (the close_fds parameter to subprocess.Popen)
Jeff
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Re: [Python-Dev] A bug in pyconfig.h under Linux?
[sent to python-list and poster] Did you follow the direction that Python.h be included before any system header? This is mentioned at least in http://docs.python.org/ext/simpleExample.html It's a crummy thing for Python to insist on, but if you can re-organize your headers to do this it should make the warnings go away. Jeff pgpClgUkWxGW5.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Get drives and partitions list (Linux)
Using /proc/partitions is probably preferable because any user can read
it, not just people who can be trusted with read access to drives, and
because the format of /proc/partitions is probably simpler and more
stable over time.
That said, what you do is
import commands
fdisk_output = commands.getoutput("fdisk -l %s" % partition)
followed by some specialized code to parse the output of 'fdisk -l'
The following code is not at all tested, but might do the trick.
# python parse_fdisk.py
/dev/hda4 blocks=1060290 bootable=False partition_id_string='Linux swap'
partition_id=130 start=8451 end=8582
/dev/hda1 blocks=15634048 bootable=True partition_id_string='HPFS/NTFS'
partition_id=7 start=1 end=1947
/dev/hda3 blocks=9213277 bootable=False partition_id_string='W95 FAT32 (LBA)'
partition_id=12 start=8583 end=9729
/dev/hda2 blocks=52235347 bootable=False partition_id_string='Linux'
partition_id=131 start=1948 end=8450
# This source code is placed in the public domain
def parse_fdisk(fdisk_output):
result = {}
for line in fdisk_output.split("\n"):
if not line.startswith("/"): continue
parts = line.split()
inf = {}
if parts[1] == "*":
inf['bootable'] = True
del parts[1]
else:
inf['bootable'] = False
inf['start'] = int(parts[1])
inf['end'] = int(parts[2])
inf['blocks'] = int(parts[3].rstrip("+"))
inf['partition_id'] = int(parts[4], 16)
inf['partition_id_string'] = " ".join(parts[5:])
result[parts[0]] = inf
return result
def main():
import commands
fdisk_output = commands.getoutput("fdisk -l /dev/hda")
for disk, info in parse_fdisk(fdisk_output).items():
print disk, " ".join(["%s=%r" % i for i in info.items()])
if __name__ == '__main__': main()
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Re: count string replace occurances
On Sun, Jun 12, 2005 at 04:55:38PM -0700, Xah Lee wrote:
> if i have
> mytext.replace(a,b)
> how to find out many many occurances has been replaced?
The count isn't returned by the replace method. You'll have to count
and then replace.
def count_replace(a, b, c):
count = a.count(b)
return count, s.replace(b, c)
>>> count_replace("a car and a carriage", "car", "bat")
(2, 'a bat and a batriage')
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Re: TKinter -- '' event executing more than once?
For me, an 'is' test works to find out what widget the event is taking
place on.
#
import Tkinter
def display_event(e):
print "event received", e.widget, e.widget is t
t = Tkinter.Tk()
t.bind("", display_event)
w = Tkinter.Entry(t)
t.destroy()
#
This program prints:
event received .-1209415348 False
event received . True
if that fails, you could compare str(e.widget) and t._w, though this can
give a false positive if you have multiple Tk() instances---each Tk()
instance is called ".".
Jeff
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Re: Hiding X windows
You may want to use a standalone program to do this. "xwit" has the ability to iconify a window which can be selected in a variety of ways. http://hpux.connect.org.uk/hppd/hpux/X11/Misc/xwit-1.0/man.html There's a direct Python interface to the X protocol in python-xlib. You could re-write the common function "Select_Window()" from dsimple.c in the X source distribution. One (old) copy is here: http://ftp.rge.com/pub/X/X11R6.4/xc/programs/xwininfo/dsimple.c Having done that, I'm not entirely sure how you proceed to hide the window. You might follow the directions in the ICCCM on how to iconify or withdraw a window (http://tronche.com/gui/x/icccm/sec-4.html#s-4.1.4), or you might follow the EWMH document (http://standards.freedesktop.org/wm-spec/wm-spec-1.4.html#id2507242) Jeff pgp14degfeFns.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Socket Speed
The machines with the 100mbps ethernet link are slightly different---Pentium 4, 2.8GHz, Python 2.2, RedHat 9. File size: 87490278 Best of 4 runs: 7.50 MB/s reported by "wget". There was other network activity and system load at the time. Jeff pgpNVPeW3ghJL.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: PyArg_ParseTuple and dict
I tried to recreate the problem based on what you described in your
message. I was unable to recreate the problem.
I wrote the following file "sjh.c":
#include
PyObject *f(PyObject *self, PyObject *args) {
PyObject *ob = NULL;
if(!PyArg_ParseTuple(args, "O", &ob)) return NULL;
Py_INCREF(Py_None);
return Py_None;
}
PyMethodDef methods[] = {
{"f", (PyCFunction)f, METH_VARARGS, "test function"},
{NULL}
};
void initsjh() {
Py_InitModule3("sjh", methods, "test module");
}
I compiled it for Python 2.3:
$ gcc sjh.c -I/usr/include/python2.3 -L/usr/lib/python2.3/config -lpython2.3
-shared -o sjh.so
and I tested it:
$ python -c 'import sjh; print sjh.f(1)'
None
$ python -c 'import sjh; print sjh.f({})'
None
$ python -c 'import sjh; print sjh.f({None: None})'
None
Jeff
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Re: GUI builders considered harmful (Was: anygui, anydb, any opinions?)
On Sun, Jun 05, 2005 at 02:38:16PM -0500, Mike Meyer wrote: [...] > The first, and most obvious, thing that GUI builders do is force the > developer to specify an exact position - if not size - for the > graphical elements of the UI. [...] Certainly some---or even most---builders work like this. But there's no reason that a GUI GUI builder can't work in terms of the more sophisticated layout algorithms that are available in most modern GUI toolkits. I've written a GUI builder for Tcl/Tk (some old versions live at http://unpy.net/~jepler/nf/ but they're very out of date). The core of the application is the part that can write Tcl source code to regenerate the screen as it's currently displayed. The user can either use graphical tools like "insert widget", "show properties", "pack earlier/later", "automatically add accelerator keys", or script the thing by typing in Tcl. Want to use the grid manager? Fine, go ahead. The graphical interface to the grid command may be poor, but the commandline interface works great. When things are as you want them, just "save", and you can trivially "source" the resulting Tcl code from your Tcl/Tk app. I'm not trying to evangelize Tcl/Tk above any other language/toolkit, but I am saying that by pairing an interpreted language with a GUI toolkit, you can get a powerful GUI builder that instantly has top-notch scrptability and also the guarantee that you can use the powerful features of the GUI toolkit. I didn't do a survey of existing software before writing mine, but I don't know of another builder that takes this kind of approach. I wonder why not. Jeff pgpMiqACxrAvI.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Socket Speed
300KB/s sounds dreadfully low. I simply ran "python /usr/lib/python2.3/SimpleHTTPServer.py &", then "wget -O /dev/null http://0.0.0.0:8000/70megfile";. On the best of 4 runs (when the file was cached) wget measured 225.20MB/s. The hardware is a Pentium-M laptop with 768MB RAM runnng at 1.5GHz. The OS is Fedora Core 2, kernel 2.6.12-rc5, Python 2.3. Jeff pgpqnaSsnl0tn.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: method = Klass.othermethod considered PITA
On Sat, Jun 04, 2005 at 10:43:39PM +, John J. Lee wrote: > 1. In derived classes, inheritance doesn't work right: Did you expect it to print 'moo'? I'd have been surprised, and expected the behavior you got. > 2. At least in 2.3 (and 2.4, AFAIK), you can't pickle classes that do >this. In all the versions of Python I've used, classes are pickled by name. This example you wrote doesn't pose any special problem when pickling. >>> pickle.dumps(A) 'c__main__\nA\np0\n.' >>> pickle.dumps(B) 'c__main__\nB\np0\n.' Jeff pgpIxRuaKzVxS.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: thread vs GC
I suspect that getting the threads to die will be tricky, and as written the thread holds a reference to the 'primegen' instance (this part can be cured, but it still doesn't ever make the thread exit). Instead of figuring out how to get this to clean itself up, why not make sure you only make one 'primegen' instance, using one of the various singleton patterns? There may still be something "uncollectable", but at least there will only be one. Jeff pgpguzGVLqvop.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Easy way to detect hard drives and partitions in Linux
You're not going to find a single portable "unix" way of doing this. The format of /etc/fstab and /etc/mtab are pretty portable, but they only list mountable/mounted partitions, not all partitions. In addition to the linux possibilities mentioned in another reply, there is also /proc/partitions. Finally, if you only want to recognize FDISK.EXE-type partitions (used by many types of Linux, though that seems to be changing in Fedora Core 4), it shouldn't be hard to write a Python program to read the partition table directly from the disk. The details will be readily available online. Jeff pgpUHTjvdDpAs.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: TkInter Listbox Widget Formatting
This isn't an option in the stock Tk listbox or any of the alternatives I know of offhand (bwidget ListBox, TixTList). The TkTable widget, which can also display multiple columns, can select different justifications, either for the whole table, or for single cells. I've never used TkTable with Python/Tkinter, however. Jeff pgpJEp4ubX0Ge.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Unicode string in exec
First off, I just have to correct your terminology. "exec" is a statement, and doesn't require parentheses, so talking about "exec()" invites confusion. I'll answer your question in terms of eval(), which takes a string representing a Python expression, interprets it, and returns the result. In Python 2.3, the following works right: >>> eval(u"u'\u0190'") u'\u0190' Here, the string passed to eval() contains the literal LATIN CAPITAL LETTER OPEN E, and the expected unicode string is returned The following behaves "surprisingly": >>> eval(u"'\u0190'") '\xc6\x90' ... you seem to get the UTF-8 encoding of the unicode. This is related to PEP 263 (http://www.python.org/peps/pep-0263.html) but the behavior of compile(), eval() and exec don't seem to be spelled out. Jeff pgp7R8SrUm3oO.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: scripting browsers from Python
I wanted to have a Python program make my browser do a POST. I am using Firefox on Linux. Here's what I did: * Prepare a HTML page on the local disk that looks like this: http://www.example.com/cgi-bin/example.cgi";> Submitting form... * Point the webbrowser at it. In my case, the webbrowser module didn't work immediately so I just used os.system() with a hardcoded browser name for it Jeff pgpRarqrD1itP.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: exit after process exit
You might want
os.spawnv(os.P_WAIT, "a.exe", ["a.exe"])
os.system("a.exe")
Jeff
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Re: Strange behaviour of floating point constants in imported modules
This may be relevant to the problems you're seeing: https://sourceforge.net/tracker/?func=detail&atid=305470&aid=774665&group_id=5470 The short story, as the tracker item paints it, is that setting LC_NUMERIC to anything other than 'C' can give results like the ones you describe---Python itself should never do this, but third parties code may. A web search for python LC_NUMERIC should turn up more about this topic, probably even some past threads on this mailing list/newsgroup. Jeff pgpBXVBWgbrnm.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Shift-JIS to UTF-8 conversion
On Fri, May 20, 2005 at 12:16:15AM -0700, [EMAIL PROTECTED] wrote: > Hello, I think the answer is basically correct but shift-jis is not a > standard part of Python 2.3. Ah, I was fooled --- I tested on Python 2.3, but my packager must have included the codecs you went on to mention. Jeff pgp4qvXpgMoKr.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Shift-JIS to UTF-8 conversion
I think you do something like this (untested): import codecs def transcode(infile, outfile, incoding="shift-jis", outcoding="utf-8"): f = codecs.open(infile, "rb", incoding) g = codecs.open(outfile, "wb", outcoding) g.write(f.read()) # If the file is so large that it can't be read at once, do a loop which # reads and writes smaller chunks #while 1: #block = f.read(4096000) #if not block: break #g.write(block) f.close() g.close() Jeff pgp72dlRWI08A.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Tkinter special math chars
On Thu, May 19, 2005 at 12:56:12PM -0500, phil wrote:
> Why is it so slow? (RH Linux, 2.4.20, 1.6Ghz AMD)
> 3/4 second slower to display widget w/unicode,
> even if I encode u'\u221e'
u'\u221e' vs u'\N{INFINITY}' should make no noticible run-time
difference--they both specify exactly the same string, and the decoding
takes place at the time the script or module is byte-compiled.
What Tk does at runtime is inspect a large number of fonts until it
finds one with the desired character---or all the fonts, if the
character doesn't exist. Querying all the fonts on your
system can take quite a bit of time. I believe that Tk caches this
information until program exit, or at least as long as the font is in
use, and characters that are nearby in their unicode values will be
resolved at the same time.
I'm not aware of a good explanation of the low-level font handling in
Tk; The information in the above paragraph was gleaned by reading the
source code (tkUnixFont.c and tkWinFont.c).
Jeff
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Re: Tkinter special math chars
I wrote the following code:
import Tkinter
t = Tkinter.Label()
t.configure(
text=u"As the function approaches \N{INFINITY}, \N{HORIZONTAL
ELLIPSIS}")
t.pack()
t.mainloop()
It worked for me on Windows NT 4.0 with Python 2.4, and on RedHat 9 with
a self-compiled Python 2.3, showing an infinity symbol and an ellipsis.
u'\N{...}' stands for the Unicode character named '...'. Unicode.org
(and other sites) have lists of Unicode character names.
Tk tries very hard to find the requested character in some font
available on the system, but when it fails it just displays a unicode
escape sequence like "\u220e" (instead of the END OF PROOF symbol, in
this case), and there's really no way for Python to find out and fall
back in some graceful way.
Relying on this behavior, here's a somewhat-falliable way to detect the
presence of a symbol in the font used in a given widget:
def symbol_exists(s, w, f = None):
if f is None:
f = w.cget("font")
width_symbol = w.tk.call("font", "measure", f, s)
width_bench = w.tk.call("font", "measure", f, "000")
return width_symbol < width_bench
This finds the width in pixels of the given symbol (s) and the string "000", in
the font f. If the width of the symbol is smaller, then it's probably
available.
If it's wider, then it's probably rendered as an escape sequence like "\u220e".
This is falliable because there's no guarantee that the symbol would not be as
wide as 000, but also it's possible for some escape code (say \u) to be
narrower than 000. Neither of these seem very likely in practice.
Jeff
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Re: Byte-operations.
In Python, "chr" gives a 1-byte string from a small integer, "ord" does the reverse. Strings are concatenated with "+" and substrings are taken with the slice operator, s[pos1:pos2]. I'm not a visual basic expert, but it looks like these are the operations the code below performs. Jeff pgpWpqb24ZucD.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: iso_8859_1 mystery/tkinter
this isn't about the "sign bit", it's about assumed encodings for byte strings.. In iso_8859_1 and unicode, the character with value 0xb0 is DEGREE SIGN. In other character sets, that may not be true---For instance, in the Windows "code page 437", it is u'\u2591' aka LIGHT SHADE (a half-tone pattern). When you write code like x = '%c' % (0xb0) and then pass x to a Tkinter call, Tkinter treats it as a string encoded in some system-default encoding, which could give DEGREE SIGN, could give LIGHT SHADE, or could give other characters (a thai user of Windows might see THAI CHARACTER THO THAN, for instance, and I would see a question mark because I use utf-8 and this is an invalid byte sequence). By using x = u'%c' % (0xb0) you get a unicode string, and there is no confusion about the meaning of the symbol---you always get DEGREE SIGN. Jeff pgpsAO42RPHy5.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Interaction between TclTk editor with Python code
One way to get a handle on some Tcl variables from Python is to create Tkinter.Variable instances with the names of the existing Tcl variables (normally, the variable names are chosen arbitrarily). Once you've done this, you can do things like add variable traces (the trace_variable method) on the Python side. One thing to be aware of is that the Python object's __del__ will unset the variable on the Tcl side. Also, this code sets an initial value for the variable which may or may not be appropriate in your application. The code below was ripped from a larger application, so it may or may not work without modification. Jeff # This code is in the public domain from Tkinter import * def makevar(master, name, klass, *default): self = newinstance(klass) self._master = master self._tk = master.tk self._name = name if default: self.set(default[0]) else: self.set(self._default) return self def makebool(master, name, *default): return makevar(master, name, Tkinter.BooleanVar, *default) def makeint(master, name, *default): return makevar(master, name, Tkinter.IntVar, *default) def makefloat(master, name, *default): return makevar(master, name, Tkinter.DoubleVar, *default) def makestring(master, name, *default): return makevar(master, name, Tkinter.StringVar, *default) pgp8S84d8ZZDq.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Recommended version of gcc for Python?
Most versions of gcc should be just fine to compile Python. Python is targeted at ANSI/ISO C compilers, but does not yet use any C99 features. I don't think there was ever such a thing as "gcc 3.5"; http://gcc.gnu.org/ lists 4.0 as the "current release series" and 3.4.3 as the "previous release series". I'd steer clear of this version. I recommend using the default compiler of your distribution, unless you know of a specific reason to use a different one. Jeff pgpIOvlvJwm7i.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Precision?
If you want to do decimal arithmetic, use the decimal module which is
new in Python 2.4.
Python 2.4 (#1, Jan 22 2005, 20:45:18)
[GCC 3.3.3 20040412 (Red Hat Linux 3.3.3-7)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from decimal import Decimal as D
>>> D("1.0") + D("3.0") + D("4.6")
Decimal("8.6")
>>>
when you write '4.6', you get a binary floating-point number which is
not equal to the decimal number 4.6.
>>> 4.6
4.5996
>>> 4.6 == D("4.6")
False
Jeff
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Re: How "return" no return ?
At the interactive prompt, a result is printed when both these things are true: * The entered code is an expression, not any other kind of statement * The result of the expression is not 'None' If an expression occurs, information about it will be printed instead. So the interpreter won't print a result for >>> a = 3# because it's an assignment statement >>> def f(): return # because it's a 'def' statement >>> None # because the result of the expression is 'None' >>> f() # because the result of the expression is 'None' Your example >>> int a is not Python, but if it was it would probably be a non-expression statement, and thus never print a result in the interpreter. Jeff pgpYRHXaq9ZxI.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Using TCL files in Python ?
While I've never used it, there *is* a Tix module in Python which
appears to wrap the widgets provided by Tix. In Fedora Core 2, Python
doesn't seem to be configured to use Tix OOTB but a one-liner (that
should be harmless elsewhere) does make it work.
These classes are defined in the Tix module:
['Shell', 'Meter', 'TixSubWidget', 'ExFileSelectDialog',
'NoteBookFrame', 'DirSelectDialog', 'Control', 'LabelEntry',
'ButtonBox', 'ScrolledTList', 'Select', 'HList', 'Balloon', 'PopupMenu',
'DirSelectBox', 'ComboBox', 'ScrolledWindow', 'Grid', 'CheckList',
'DialogShell', 'Tree', 'DirList', 'ResizeHandle', 'NoteBook',
'ListNoteBook', 'ScrolledGrid', 'FileEntry', 'ScrolledHList', 'DirTree',
'OptionMenu', 'ScrolledText', 'LabelFrame', 'FileSelectBox',
'ScrolledListBox', 'InputOnly', 'PanedWindow', 'StdButtonBox',
'FileSelectDialog', 'CObjView', 'ExFileSelectBox', 'TList']
Here's what I did to get a simple Tix widget to work:
>>> import Tkinter, Tix
>>> t = Tkinter.Tk()
>>> t.tk.call("package", "require", "Tix")
'8.1.8.4'
>>> u = Tix.ComboBox(t)
>>> for i in range(30): u.insert("end", "Item %d" % i)
...
>>> u.pack()
Jeff
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Re: [HELP] Tkinter Application Minimized to System Tray :)
Tk, the library that Tkinter wraps, does not offer a way to "minimize to the taskbar". Jeff pgp3ATXnxg0dO.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: New Python regex Doc (was: Python documentation moronicities)
To add to what others have said:
* Typos and lack of spell-checking, such as "occurances" vs "occurrences"
* Poor grammar, such as "Other characters that has special meaning
includes:"
* You dropped version-related notes like "New in version 2.4"
* You seem to love the use of s, while docs.python.org uses them
sparingly
* The category names you created, "Wildcards", "Repetition Qualifiers",
and so forth, don't help me understand regular expressions any better
than the original document
* Your document dropped some basic explanations of how regular
expressions work, without a replacement text:
Regular expressions can be concatenated to form new regular
expressions; if A and B are both regular expressions, then AB is
also a regular expression. In general, if a string p matches A and
another string q matches B, the string pq will match AB. [...] Thus,
complex expressions can easily be constructed from simpler primitive
expressions like the ones described here.
Instead, you start off with one unclear example ("a+" matching
"hh!") and one misleading example (a regular expression that
matches some tiny subset of valid e-mail addresses)
* You write
Characters that have special meanings in regex do not have special
meanings when used inside []. For example, '[b+]' does not mean one
or more b; It just matches 'b' or '+'.
and then go on to explain that backslash still has special meaning; I
see that the original documentation has a similar problem, but this
just goes to show that you aren't improving the accuracy or clarity of
the documentation in most cases, just rewriting it to suit your own
style. Or maybe just as an excuse to write offensive things like "[a]
fucking toy whose max use is as a simplest calculator"
I can't see anything to make me recommend this documentation over the
existing documentation.
Jeff
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Re: Best way to convert a list into function call arguments?
Your question is answered in the tutorial: http://docs.python.org/tut/node6.html#SECTION00674 4.7.4 Unpacking Argument Lists The reverse situation occurs when the arguments are already in a list or tuple but need to be unpacked for a function call requiring separate positional arguments. For instance, the built-in range() function expects separate start and stop arguments. If they are not available separately, write the function call with the *-operator to unpack the arguments out of a list or tuple: >>> range(3, 6) # normal call with separate arguments [3, 4, 5] >>> args = [3, 6] >>> range(*args)# call with arguments unpacked from a list [3, 4, 5] Jeff pgpaezewLDmEG.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: descriptor dilemma
On Wed, May 04, 2005 at 09:14:18AM -0700, Sébastien Boisgérault wrote: > > Yup ?!? Weird ... especially as: > > >>> id(c.f) == id(C.__dict__['f'].__get__(c,C)) > True Here, c.f is discarded by the time the right-hand-side of == is executed. So the object whose id() is being calculated on the right-hand-side could turn out to be the same, since the two objects have disjoint lifetimes. Here are some more cases of the same thing: >>> id([]) == id([]) 1 >>> id([]) == id([1]) 1 Jeff pgp0amP007OuW.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: A faster method to generate a nested list from a template?
Are there only a few, unchanging templates? If so, (dynamiclly) create
a function for each template. This will be nearly the fastest you can
go in Python, excluding the time to create and byte-compile the nesting
function.
# This code is in the public domain
def make_nesting_expression(l, s):
result = []
for c in l:
if isinstance(c, list):
sub, s = make_nesting_expression(c, s)
result.append(sub)
else:
result.append("l[%d]" % s)
s += 1
print "make_nesting_expression", l, result
return "[" + ",".join(result) + "]", s
def make_nesting_function(l):
return eval("lambda l: %s" % make_nesting_expression(l, 0)[0])
t = [['a1','a2'],['b1'],['c1'],['d1']]
l = [1, 2, 3, 4, 5]
f = make_nesting_function(t)
print f(l)
Jeff
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Re: How to read an integer value from a binary file?
As your 'for' loop shows, the number of items in the slice [2:5] is only
3, not 4.
Maybe you want the slice [2:6] instead.
>>> x = "xx\xb6/\0\0"
>>> struct.unpack('i', x[2:6])
(12214,)
Jeff
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Re: cgi "print statement" in multithreaded enviroment?
You could write something like class ThreadSpecificFile: def set_stdout(f): self.files[thread_id] = f def write(data): self.files[thread_id].write(data) sys.stdout = ThreadSpecificFile() where you'll have to fill out a few more things like thread_id, __init__, and a way to clean up items from self.files when a thread passes away. Jeff pgpfNtl83qNgI.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: How to track down all required shared libraries?
One poster suggests 'ldd' for executables. You can also use this on shared libraries: $ ldd /usr/lib/python2.3/lib-dynload/_tkinter.so libtix8.1.8.4.so => /usr/lib/libtix8.1.8.4.so (0x009b6000) libtk8.4.so => /usr/lib/libtk8.4.so (0x00111000) libtcl8.4.so => /usr/lib/libtcl8.4.so (0x00539000) libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x00a48000) libpthread.so.0 => /lib/tls/libpthread.so.0 (0x001de000) libc.so.6 => /lib/tls/libc.so.6 (0x001f) libdl.so.2 => /lib/libdl.so.2 (0x0052d000) libm.so.6 => /lib/tls/libm.so.6 (0x00fcf000) /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00656000) If you know what shared modules your program uses, you can "ldd" them all and find out the set of libraries they are linked to. Jeff pgpeC5PdZ34hJ.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: tkinter OptionMenu column break
I don't think that Tk's menus ever use more than one column. They certainly don't on Unix. Jeff pgpsVnvjgm3Qy.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: python equivalent of php implode
On Tue, Apr 26, 2005 at 09:59:29PM -0500, Mike Meyer wrote: > Jeff Epler <[EMAIL PROTECTED]> writes: > > > items = query_param.items() > > keys = [item[0] for item in items] > > values = [item[1] for item in items] > > Is there some reason not to do: > >keys = query_params.keys() >values = query_params.values() > > That would seem to be a lot more obvious as to what was going on. I was afraid that .keys() and .values() might not "match up" (so that the i'th key maps to the i'th value in query_param). Now that I've glanced at the documentation, I see that this *is* guaranteed[1], and I should have written the code you proposed. Jeff [1] http://docs.python.org/lib/typesmapping.html note 3 pgpxQa6k4Ldvu.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: python equivalent of php implode
It looks like php's implode(sep, seq) is like sep.join(seq) in Python. But this is a lousy way to write database queries. You should use the Python's DB-API interface's execute(statement, parameters) instead. Assuming that paramstyle is 'qmark', I think it ends up looking something like this: items = query_param.items() keys = [item[0] for item in items] values = [item[1] for item in items] # If the query parameters or the table are under # user control you must take care to validate them assert table in permitted_tables for k in query_param.keys(): assert k in permitted_keys sql = "INSERT INTO %s (%s) values %s" % ( table, ", ".join(keys), ", ".join(["?"] * len(keys)) ) conn.execute(sql, values) now you don't have to worry that you get the quoting of the values absolutely right, since db-api does it for you. Jeff pgpAH3nHgcgJw.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Why is Python not supporting full derivation of built-in file class?
This issue was discussed in another recent python-list thread, called "Writing to stdout and a log file". My second post includes a patch to Python's "fileobject.c" that made the code that started that thread work, but for reasons I mentioned in that post I didn't want to push for inclusion of my patch. I didn't check, but it will probably allow your code to work too. If you feel differently, then the thing to do is probably to submit the patch plus a test case to the sf.net patch tracker for python (sf.net/projects/python, click on "patches". you'll need a sourceforge account to submit the patch) Jeff PS I did allow the Python test suite to run to completion after I wrote that message. It didn't produce any failures or unexpected skips on my platform. pgppjD5SYuGFg.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Writing to stdout and a log file
In that case, it looks like you won't be able to get what you want
without modifying CPython. PRINT_ITEM calls PyFile_SoftSpace,
PyFile_WriteString, and PyFile_WriteObject, which all use
PyFile_Check(). It might be as simple as changing these to
PyFile_CheckExact() calls in PyFile_WriteString / PyFile_WriteObject,
but I have no idea whether the test suite still works after this change
is made. It does make this program work (it prints things from X.write):
class X(file):
def write(self, s):
print "X.write", `s`
return file.write(self, s)
import sys
x = X("/tmp/out.txt", "w")
print >>x, 42
I don't care to be the champion of this patch, or to submit it to
sourceforge; I suspect there should be a better review of PyFile_Check
vs PyFile_CheckExact uses in fileobject.c, instead of just picking the
few spots that make this usage work. Before being submitted as a patch,
a testcase should be added too. Feel free to run with this if you feel
strongly about it.
Jeff
Index: Objects/fileobject.c
===
RCS file: /cvsroot/python/python/dist/src/Objects/fileobject.c,v
retrieving revision 2.193
diff -u -u -r2.193 fileobject.c
--- Objects/fileobject.c7 Nov 2004 14:15:28 - 2.193
+++ Objects/fileobject.c20 Apr 2005 02:41:32 -
@@ -2012,7 +2012,7 @@
PyErr_SetString(PyExc_TypeError, "writeobject with NULL file");
return -1;
}
- else if (PyFile_Check(f)) {
+ else if (PyFile_CheckExact(f)) {
FILE *fp = PyFile_AsFile(f);
#ifdef Py_USING_UNICODE
PyObject *enc = ((PyFileObject*)f)->f_encoding;
@@ -2082,7 +2082,7 @@
"null file for PyFile_WriteString");
return -1;
}
- else if (PyFile_Check(f)) {
+ else if (PyFile_CheckExact(f)) {
FILE *fp = PyFile_AsFile(f);
if (fp == NULL) {
err_closed();
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Re: Writing to stdout and a log file
This variation works:
#
class Tee:
def __init__(self, *args):
self.files = args
def write(self, data):
for f in self.files:
result = f.write(data)
return result
def writelines(self, seq):
for i in seq: self.write(i)
import sys
sys.stdout = Tee(sys.stdout, open("/tmp/stdout.log", "w"))
print 'STDOUT', sys.stdout
#
It appears that the 'print' statement always uses file.write if
isinstance(sys.stdout, file). I don't know whether this has been
reported as a bug before, or if there's a reason for the current
behavior. It may be an accidental behavior that is left over from the
days when builtin types were not subclassable.
Jeff
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Re: fpectl
On Tue, Apr 19, 2005 at 02:05:11AM -0700, Sébastien Boisgérault wrote: > Thanks for this answer. > > Did you forward this info to python-dev ? I created a patch on the sf tracker. It's been responded to by several developers. You can read what they said there. http://python.org/sf/1185529 Jeff pgpzLX8Ht47YG.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Tkinter Event Types
The "type" field is related to the definition of different events in X11. In Xlib, the event structure is a "C" union with the first (common) field giving the type of the event so that the event-dependant fields can be accessed through the proper union member. Generally, you won't use this field in Tkinter programs. jeff pgpCj3ZljM90R.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: fpectl
It looks like the automatic build of the 'fpectl' module was broken
somewhere along the line, perhaps when the transition from Modules/Setup
to setup.py took place.
Once I made the change below and rebuilt, I got the fpectl module.
Furthermore, it appeared to "do something" on my Linux/x86 system:
$ ./python -c '1e200 ** 6'
OverflowError: (34, 'Numerical result out of range')
$ ./python -c 'import fpectl; print dir(fpectl); fpectl.turnon_sigfpe(); 1e200
** 6'
['__doc__', '__file__', '__name__', 'error', 'turnoff_sigfpe', 'turnon_sigfpe']
Fatal Python error: Unprotected floating point exception
Aborted
Jeff
Index: setup.py
===
RCS file: /cvsroot/python/python/dist/src/setup.py,v
retrieving revision 1.217
diff -u -u -r1.217 setup.py
--- setup.py15 Apr 2005 20:32:39 - 1.217
+++ setup.py19 Apr 2005 00:13:15 -
@@ -400,6 +400,8 @@
# select(2); not on ancient System V
exts.append( Extension('select', ['selectmodule.c']) )
+exts.append( Extension('fpectl', ['fpectlmodule.c']) )
+
# The md5 module implements the RSA Data Security, Inc. MD5
# Message-Digest Algorithm, described in RFC 1321. The
# necessary files md5c.c and md5.h are included here.
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Re: New Python regex Doc (was: Python documentation moronicities)
On Mon, Apr 18, 2005 at 01:40:43PM -0700, Xah Lee wrote: > i have rewrote the Python's re module documentation. > See it here for table of content page: > http://xahlee.org/perl-python/python_re-write/lib/module-re.html For those who have long ago consigned Mr. Lee to a killfile, it looks like he's making an honest attempt to improve Python's documentation here. Mr Lee, I hope you will submit your documentation changes to python's patch tracker on sourceforge.net. I don't fully agree with some of what you've written (e.g., you give top billing to the use of functions like re.search while I would encourage use of the search method on compiled RE objetcts, and I like examples to be given as though from interactive sessions, complete with ">>>" and "..."), but nits can always be picked and I'm not the gatekeeper to Python's documentation. Jeff pgpq9H9EDt08X.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Get the entire file in a variable - error
It's not clear to me what you mean by "the first line" (gzip does not
output a file composed of lines, its output is byte-oriented).
Printing tst.getvalue() is probably not a very useful thing to do, since
it won't do anything useful when the output is a terminal, and it will
add an extra newline if you are redirecting to a file.
At least when close()ing the GzipFile before looking at the StringIO
instance's value, I get some bytes that gunzip just fine, giving the
original string.
Here's my interactive session:
>>> import gzip
>>> import StringIO
>>> io = StringIO.StringIO()
>>> z = gzip.GzipFile("test.gz", "w", 5, io)
>>> z.write("""\
... Python 2.2.2 (#1, Feb 24 2003, 19:13:11)
... [GCC 3.2.2 20030222 (Red Hat Linux 3.2.2-4)] on linux2
... Type "help", "copyright", "credits" or "license" for more information.
... """)
>>> z.close()
>>> from os import popen
>>> popen("gunzip -dc", "w").write(io.getvalue())
Python 2.2.2 (#1, Feb 24 2003, 19:13:11)
[GCC 3.2.2 20030222 (Red Hat Linux 3.2.2-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
I don't know anything about your database or its "LONG field".
Depending on the database software there could be additional problems
with embedded NULs, for instance.
Jeff
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Re: Why won't someone step up and make use of the Free tools (was Re: Python 2.4 killing commercial Windows Python development ?)
On Tue, Apr 12, 2005 at 08:25:58PM +, Bengt Richter wrote: > But credit where due. Someone has stepped up to a large chunk of the problem: > >http://jove.prohosting.com/iwave/ipython/pyMinGW.html Yay. I'm glad somebody *is* doing this. Maybe all that is needed is to "get the word out". Some prepackaged binaries would be nice, however. Jeff pgpScTLdxbgkf.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: Tkinter "withdraw" and "askstring" problem
The answer has to do with a concept Tk calls "transient". wm transient window ?master? If master is specified, then the window manager is informed that window is a transient window (e.g. pull-down menu) working on behalf of master (where master is the path name for a top-level window). If master is specified as an empty string then window is marked as not being a transient window any more. Otherwise the command returns the path name of windowâs current master, or an empty string if window isnât currently a transient window. A transient window will mirror state changes in the master and inherit the state of the master when initially mapped. It is an error to attempt to make a window a transient of itself. In tkSimpleDialog, the dialog window is unconditionally made transient for the master. Windows is simply following the documentation: The askstring window "inherit[s] the state of the master [i.e., withdrawn] when initially mapped". The fix is to modify tkSimpleDialog.Dialog.__init__ to only make the dialog transient for its master when the master is viewable. This mirrors what is done in dialog.tcl in Tk itself. You can either change tkSimpleDialog.py, or you can include a new definition of __init__ with these lines at the top, and the rest of the function the same: def __init__(self, parent, title = None): ''' the docstring ... ''' Toplevel.__init__(self, parent) if parent.winfo_viewable(): self.transient(parent) ... # Thanks for being so dynamic, Python! tkSimpleDialog.Dialog.__init__ = __init__; del __init__ Jeff pgp4ueSCXQcCg.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Why won't someone step up and make use of the Free tools (was Re: Python 2.4 killing commercial Windows Python development ?)
I'm sorry that this is going to come out sounding like a flame, but it seems to me that there today only a few technical problems remaining with Python when built with mingw32. If one of the people who has expressed such deep concern about this "msvcr71.dll" problem would simply install the Free tools and start putting patches on sourceforge, it's quite possible that for the next 2.4.x release the mingw32 "port" could be a first-rate one, and suitable for the uses that the posters in this thread have mentioned. Since mingw32 is Free (gpl and other licenses for tools, public domain libraries and copyrighted headers with "no restrictions for programs" built using the headers) anyone can install and use these tools and mingw creates no new problems with distribution of the resulting binary, whether the final product is Free or proprietary. (Admittedly I don't know anything about whether "win32all" builds under mingw32, and it's not clear whether binary compatibility with extensions built by microsoft compilers is an easy goal either) http://www.mingw.org/ Jeff pgplhycX3JBjH.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: help: loading binary image data into memory
probably something like this: (untested) def make_ftplib_callback(f): def callback(block): f.write(block) return callback img = cStringIO.StringIO() retrbinary( "get ???", make_ftplib_callback(img)) Jeff pgpaecaxnsqYB.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
Re: curious problem with large numbers
You may want to read
http://www.python.org/peps/pep-0754.html
Part of the text reads
The IEEE 754 standard defines a set of binary representations and
algorithmic rules for floating point arithmetic. Included in the
standard is a set of constants for representing special values,
including positive infinity, negative infinity, and indeterminate or
non-numeric results (NaN). Most modern CPUs implement the IEEE 754
standard, including the (Ultra)SPARC, PowerPC, and x86 processor
series.
Currently, the handling of IEEE 754 special values in Python depends
on the underlying C library. Unfortunately, there is little
consistency between C libraries in how or whether these values are
handled. For instance, on some systems "float('Inf')" will properly
return the IEEE 754 constant for positive infinity. On many systems,
however, this expression will instead generate an error message.
Jeff
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Re: Read 16 bit integer complex data
You may want to use the 'numeric' or 'numarray' extensions for this.
The page on numarray is here:
http://www.stsci.edu/resources/software_hardware/numarray
numarray doesn't support "complex 16-bit integer" as a type, but you can
get a complex, floating-point valued array from your integer values.
Here's how, with a bit of explanation along the way:
I created a small example: a vector of 2 "complex 16-bit integers"
in the native byte-order.
>>> s = struct.pack("", 1, 2, 3, 4)
>>> s
'\x01\x00\x02\x00\x03\x00\x04\x00'
I think this stands for the vector <1+2j, 3+4j> according to what you
wrote.
I can turn this into a 4-element numarray like so:
>>> numarray.fromstring(s, "s")
array([1, 2, 3, 4], type=Int16)
and extract the real and complex parts with extended slices:
>>> t[1::2] # take the items 1, 3, ..., 2*n+1 i.e., the complex parts
array([2, 4], type=Int16)
This expression forms the complex 64-bit floating point 2-element array
from 't':
>>> u = t[0::2] + t[1::2] * 1j
>>> u
array([ 1.+2.j, 3.+4.j])
If the byte-order of the file is different from the native byte order,
you can byte-swap it before forming the complex FP array:
>>> t.byteswap()
>>> t
array([ 256, 512, 768, 1024], type=Int16)
Jeff
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Re: Resticted mode still active (error?)
Is there a script that causes this problem, without using mod_python or jepp? If so, please attach it to the sourceforge bug. http://sourceforge.net/tracker/index.php?func=detail&aid=1163563&group_id=5470&atid=105470 pgpiWdvwwFmcD.pgp Description: PGP signature -- http://mail.python.org/mailman/listinfo/python-list
