Mailman 3 February 2008 - Python-list

Re: code blocks in Python
by hungjunglu＠yahoo.com March 25, 2022

March 25, 2022

Skip Montanaro <skip(a)pobox.com> wrote in message news:<mailman.1035.1069703636.702.python-list(a)python.org>... > > You should be able to express the desired semantics of your extension to the > language without requiring us to execute code. I have yet to see an > explanation of why you want > > def c: > x += 1 > > added to the language. I can guess that it binds c to a "code block". How > do I use it? The above is illegal syntax in Python today. Am I supposed to > guess how to use it? That has nothing to do with compile(). Am I supposed > to run it with the exec statement or do you envision me just inserting > > c > > into my code? Skip: being you a Python old timer, I think you are just grumbling for no good reason. :) Before anything else, people are already jumping into implementation details, optimization, syntax, etc. I am barely starting to look at whether there have been previous existing efforts, and if so, why were they discarded, etc. > > What exactly have you given me that I couldn't have done with > > x = 1 > x += 1 > I come back again to repeat it one more time: the compile() function already exists and works in Python. Before you do your posting, please think about the compile() function first. (Do I need to say it one more time? I don't mind.) So, let me try to pretend I am Skip Montanaro, and follow through with the process. (a) OK, I have been told that compile() function exists in Python. (b) I am complaining that I can do x = 1 x += 1 without resorting to codeblocks. So there is no need for codeblocks. Codeblocks are useless, good for nothing. (c) OK, one more time, I have been told that compile() function exists and works in Python. Everytime I talk about codeblocks, I need to think about the compile() function first. (d) Aha! So by analogy, there is no need for the compile() function in Python. I get it now! (e) Wait a second... searching through the Python newsgroup archive I find hundreds if not thousands of messages related to the usage of the compile() function. So the compile() function can't be useless. Either thousands of Python users are wrong, or I have not been careful in my thinking process. (f) Hmm... let me look at those messages and try to understand how people are using the compile() function. (g) Aha! The compile() function is not useless. I know how to use it, now. (h) Aha! Codeblocks are not useless. (i) Aha! So codeblocks are analogous to the compile() function, the only difference is that codeblocks are compiled at compile time. The compile function compiles the code string at runtime. (j) Wait, I think Hung Jung has said everything before in his messages. Bingo! Now you get it. Hung Jung

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Strange terminal behavior after quitting Tkinter application
by Chris Nov. 3, 2020

Nov. 3, 2020

Hi, I'm puzzled by some strange behavior when my Python/Tkinter application quits (on linux): the terminal from which I started Python is messed up. If start up python, then import the code below, then start the program with Application(), then click the Quit button, my terminal never prints anything again (such as commands I type). <code> import Tkinter import sys class Application(Tkinter.Tk): def __init__(self,**config): Tkinter.Tk.__init__(self,**config) Tkinter.Button(self,text="Quit",command=self.quit_application).pack() def quit_application(self): sys.exit() </code> Can anyone tell me what I'm doing wrong? Thanks for your help. Chris

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IP address to binary conversion
by Jeroen Wolff May 9, 2020

May 9, 2020

Hi, Can somebody help me (a newbee) to convert an ip address to is 32 bits representation? i would like to store these 32bits interger into a MYSQL database together with the mask. Jeroen

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embedding python - PyImport_ImportModule returns null
by jkpangtang＠yahoo.com March 28, 2019

March 28, 2019

I am trying to embed python within a c program, but I can't get PyImport_ImportModule() command to load my module. Please let me know what I'm doing wrong. -- #file func.py def func1(): print "inside func1()" -- //main.c int main() { PyObject *pFunc, *pModule; Py_Initialize(); pModule=PyImport_ImportModule("func"); //fileread.py if(pModule==NULL) { PyErr_Print(); fprintf(stderr,"Failed to load \"%s\"\n","func"); } //etc.... } --- Both main.c and func.py are in the same directory. I run main and get the error Failed to load "func", meaning that PyImport_ImportModule returns NULL. What am i doing wrong? Thanks in advance for the help

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Python Interview Questions
by Krypto Jan. 10, 2019

Jan. 10, 2019

Hi, I have used Python for a couple of projects last year and I found it extremely useful. I could write two middle size projects in 2-3 months (part time). Right now I am a bit rusty and trying to catch up again with Python. I am now appearing for Job Interviews these days and I am wondering if anybody of you appeared for a Python Interview. Can you please share the questions you were asked. That will be great help to me. Thanks,

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SWIG+Distutils - no harmony?
by m.bless＠gmx.de July 7, 2018

July 7, 2018

Getting courageous I try building 'example.pyd' from the SWIG 'Simple Example' using SWIG and the Distutils. Looks promising but doesn't succeed. I didn't modify 'example.c' and 'example.i'. Problems/questions: (1) Is 'setup.py' ok? (2) BEWARE: What's really shocking: After see (unsuccessful) python setup.py build -cmingw32 the original 'example.c' is GONE AND AWAY - replaced by the wrapper. (3) What's going wrong? Martin Sources und logs following: >----------<>----------<>----------< # setup.py # mb: Is this ok? import distutils from distutils.core import setup, Extension #from distutils.extension import Extension setup(name = "Example 'Simple' from the SWIG examples", version = "2.2", ext_modules = [Extension("example", ["example.i"])]) >----------<>----------<>----------< /* File : example.i */ %module example extern int gcd(int x, int y); extern double Foo; >----------<>----------<>----------< /* File : example.c */ /* A global variable */ double Foo = 3.0; /* Compute the greatest common divisor of positive integers */ int gcd(int x, int y) { int g; g = y; while (x > 0) { g = x; x = y % x; y = g; } return g; } >----------<>----------<>----------< C:\python Python 2.2 (#28, Dec 21 2001, 12:21:22) [MSC 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> >----------<>----------<>----------< swig -version SWIG Version 1.3.10u-20011211-2004 Copyright (c) 1995-1998 University of Utah and the Regents of the University of California Copyright (c) 1998-2001 University of Chicago Compiled with CC >----------<>----------<>----------< >python setup.py build -cmingw32 running build running build_ext building 'example' extension swigging example.i to example.c c:\pyext\swig\swig.exe -python -dnone -ISWIG -o example.c example.i c:\mingw\bin\gcc.exe -mno-cygwin -mdll -O -Wall -IC:\PYTHON22\include -c example.c -o build\temp.win32-2.2\Release\example.o writing build\temp.win32-2.2\Release\example.def c:\mingw\bin\gcc.exe -mno-cygwin -mdll -static -s build\temp.win32-2.2\Release\example.o build\temp.win32-2.2\Release\example.def -LC:\PYTHON22\libs -lpython22 -o build\lib.win32-2.2\example.pyd swig: Warning. -dnone option deprecated. example.c: In function `SWIG_UnpackData': example.c:363: warning: `uu' might be used uninitialized in this function example.c: In function `SWIG_ConvertPtr': example.c:429: warning: suggest explicit braces to avoid ambiguous `else' example.c:432: warning: suggest explicit braces to avoid ambiguous `else' example.c:438: warning: suggest explicit braces to avoid ambiguous `else' example.c: At top level: example.c:154: warning: `SWIG_TypeQuery' defined but not used example.c:385: warning: `SWIG_ConvertPtr' defined but not used example.c:468: warning: `SWIG_ConvertPacked' defined but not used example.c:537: warning: `SWIG_MakeShadow' defined but not used build\temp.win32-2.2\Release\example.o(.text+0xbda):example.c: undefined reference to `gcd' build\temp.win32-2.2\Release\example.o(.text+0xc35):example.c: undefined reference to `Foo' build\temp.win32-2.2\Release\example.o(.text+0xc6b):example.c: undefined reference to `Foo' build\temp.win32-2.2\Release\example.o(.text+0xc71):example.c: undefined reference to `Foo' error: command 'gcc' failed with exit status 1 >----------<>----------<>----------<

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merits of Lisp vs Python
by Mark Tarver Jan. 12, 2018

Jan. 12, 2018

How do you compare Python to Lisp? What specific advantages do you think that one has over the other? Note I'm not a Python person and I have no axes to grind here. This is just a question for my general education. Mark

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copy locked files
by rubbishemail＠web.de Aug. 31, 2017

Aug. 31, 2017

Hello, do you know of any way to copy locked / opened files under win xp? I know there is something like "Volume Shadow Copy" but I don't know how to use it. Maybe someone already has a python solution? Many thanks Daniel

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Re: strange behaviour when writing a large amount of data on stdout
by bokr＠oz.net April 11, 2017

April 11, 2017

On Wed, 23 Nov 2005 18:18:34 +0100, "Fredrik Lundh" <fredrik(a)pythonware.com> wrote: >Manlio Perillo wrote: > >> >>>>> print data >> >> >> >> Traceback (most recent call last): >> >> File "xxx", line xxx, in ? >> >> print data >> >> IOError: [Errno 12] Not enough space >> > >> >errno 12 is ENOMEM (that is, the system did not have enough memory >> >to finish an operation). >> >> However I think the error message is not a good one. >> Better a "Not enough memory" > >the message text is provided by the operating system (or rather, by >the C library). I'm not sure rewriting error messages is a good thing... > >(if Python itself runs out of memory, it'll raise a MemoryError instead) > Maybe there's a bare except: somewhere blocking earlier & perhaps more informative messages? If windows has been running a long time (a few days or a week may be long ;-) it may get fragmented in some smallish memory arena reserved for special things (I forgot what versions, but I wouldn't be surprised if something still had s specialized limit). Does the program involve dynamic generation of desktop icons by any chance? Especially a lot of large true-color ones? I have some faint inkling of some correlation of that and memory problems with still huge amounts of heap memory available. Has the OP rebooted and just run the offending program alone? BTW, if the OP wants to find out how much memory is on the windows system, the amount of memory probably shows in the "about" window of the task manager (the NT task manager will give you a scrolling real-time graph of different kinds of memory usage as well). Also if the OP has windows word editor (probably winword.exe will start it from the console command line), the "about" dialog may have a "system info ..." button that will show memory and a lot more. What that button runs is C:\Program Files\Common Files\Microsoft Shared\MSInfo\MSINFO32.exe on my system. Since it's accessible from Word, I wouldn't think it would be too unsafe to run, but I guess the OP might not want to start diagnostic things on arbitrary devices etc., if that's accessible from his session. Regards, Bengt Richter

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how to create IPictureDisp objects with python?
by Felix Jan. 4, 2017

Jan. 4, 2017

i try to host an activex control in my program . the control has a picture property which only accepts "IPictureDisp" interfaces. does anybody know how to create IPictureDisp objects? thanks.

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