Re: is python Object oriented??

[Marc 'BlackJack' Rintsch]

On Sat, 31 Jan 2009 15:28:14 -0800, thmpsn.m.k wrote:

> On Jan 31, 2:27 pm, Christian Heimes  wrote:
>> Do you honestly believe that C++'s private members are really private?
>> Privateness is only enforced during parsing time. Nobody can stop you
>> from messing around with header files or memory. You can still access
>> and modify private members but it's all messy and ugly. Even C# and
>> .NET don't stop you from doing nasty things from unmananged assemblies.
> 
> I don't know how you would do it in C# (or Java for that matter).

In Java you can use reflection to get your fingers on private fields.

> In C++ you can play with pointers to "get at" some memory location
> somewhere in the object.
> [Snipped pointer fiddling explanation]
> So: Sometimes it may work, usually it will be unsafe and/or non-
> portable, and in most cases the procedure will look complicated.

Or ``#define private public`` before including the header files.  Which 
doesn't look complicated to me.

> It certainly isn't something I'd try in a real application. However, it
> WOULD be tempting to access the member if the language allows me to just
> write:
> 
> print "obj.b =", obj.b
> 
> and be done with it.

And that's perfectly okay, because the author would have prepended an 
underscore to `b` if you should not mess with it.

> Personally, in Python, I use double underscores for "private" members,
> so the above would look like:
> 
> print "obj.b =", obj._NonPOD__b
> 
> but it's still easier than the C++ example.

The name mangling is there to prevent name clashes, not to make 
attributes inaccessible.  It's useful for mixin classes for example.

>> Seriously, 'private' and 'protected' are merely tools to stop bad
>> programmers from doing bad stuff. And the serve as documentation, too.
> 
> It's not just documentation. For example, suppose you're reading a class
> definition and see the declaration of a veryInterestingMember and forget
> that you're not supposed to access it. If you try to access it, the
> compiler will give you a diagnostic message at compile time.

I can't forget that because if I'm not supposed to access it, its name 
would be `_very_interesting_member`.  I don't have to wait till compile 
time to see that, it is really obvious at the time I write the code to 
access it, or decide not to because it is not part of the API.

Ciao,
Marc 'BlackJack' Rintsch
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what IDE is the best to write python?

[mcheun...@hotmail.com]

Hi all
   what IDE is the best to write python?
thanks
from Peter (mcheun...@hotmail.com)
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Re: socket.unbind or socket.unlisten? - socket.error: (48, 'Address already in use')

[Laszlo Nagy]

8<--

  

...  Setting the
SO_REUSEADDR flag on POSIX fixes this problem (don't set it on Windows,
though).



Why not?  I have been merrily setting it, and I have not noticed anything weird.
(yet)
  
Please see my original post. I specifically stated that I do not want to 
use setsockopt and be able to listen on the same port from many 
processes. I knew that I could use SO_REUSEADDR, but I'm heistating to 
do so. I must guarantee that only one process listens on a given port at 
the same time.


Maybe I could use some kind of locking, but it would be too difficult:

- mutexes are great but they are platform dependent and they are not in 
the standard lib
- the listening processes do not see each other's home directory so file 
locking cannot be used for this
- these processes will probably listen on many ports at the same time, 
it is also a problem with mutexes/file locks (who wants 50 lock files to 
be created?)



Best,

  Laszlo


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Re: Embedding numpy works once, but not twice??

[r]

> Embedding numpy works once, but not twice??

That's what she said!
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PyNutButter BETA 1.0.0 - Automates CSV data Importation into any website http/https and/or mysql database

[alex goretoy]

Introducing PynutButter BETA 1.0.0

Automates csv data importation into any website. Or your money back.
Programs like this idea of a program I have here cost $2500. Pynutbutter is
opensource. You can use the code anyway you want. As long as I get my credit
where it is due. I've worked on this project for roughly 1.5 years now. This
is an idea I tried in 2 languages. PHP and python, now.

No matter how much data in your csv file.
No matter what the field names are.
No matter how data is formatted

With PyNutButter you  can parse this data in custom functions and then send
it to its destinations.
You can map all the csv file headers to fields of a html page.
It loops for each line in the csv file and imports your data.

You must configure your configuration and create custom functions that you
can call from this configuration.

I've uploaded all the main files, except my configuration(I am working on
examples and making the main project page better)

You can find this project here:

http://code.google.com/p/pynutbutter/



I've worked long and hard on this application and the idea behind it. Any
help making this tool better would be greatly appreaciated.

Please let me know what you this of this tool. Any ideas/features are also
always welcome.

I also have a presentation I am working on for this tool. I hope to find a
nice job. This tools is very powerfuls. I was think next to try it with
scapy. That would be sweet. You can add custom flavors(data parsing/sending
libraries). My goal for this tool was to make everything as dynamic as
possible. calling of functions and dealing with parsed data in functions.
Only reason why I built is because I needed a tool like this. I know someone
else woulnd't mind having a tool like this either, so here you go. If you
can please donate or something somehow.

Upcoming Features:
use of parsed data from more than one file at a time.
pyGTK for ease of configuration creation(any help?)
gui creation of custom functions
automatic form parsing based on given urls in config

-Alex Goretoy
http://www.alexgoretoy.com
somebodywhoca...@gmail.com
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Re: Embedding numpy works once, but not twice??

[David Cournapeau]

On Sun, Feb 1, 2009 at 2:47 PM, Deepak Chandran
 wrote:
> I have a program in which I have successfully embedded Python. Now, I want
> to include NumPy as well (and other modules). I am able to import numpy
> once. Then I close the python console in my program and then re-open it.
> When I try to import numpy for a second time, the program crashes. Below is
> a simple version of the problem.
> The main() import numpy twice. The first import works fine -- prints "no
> errors.". But the second load crashes the program. What is going on here?
>
> By the way, this is all in Windows (XP and Vista have same problem) using
> python25.dll (since numpy does not work for python26.dll). I am using MinGW
> compiler.

FYI, numpy can work with python 2.6 if you build from recent svn.
numpy 1.3.0 will have 2.6 binaries

I can't really help you for your problem, I am not familiar with
python embedding. But inside python, when doing a double import,
doesn't python check against double import (e.g. the second time, it
does almost nothing) ? Is this specific to numpy, or other python
modules do that as well ?

cheers,

David
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Re: nth root

[Paul Rubin]

"Tim Roberts"  writes:
> for root in powersp:
> nroot = round(bignum**(1.0/root))
> if bignum==long(nroot)**root:
>  .
> which is probably very inefficient, but I can't see anything better.

Actually that will not be accurate enough to know if bignum is, say, a perfect 
square.
You will have to do the small-power tests at full precision (or use a fancy 
algorithm).
Larger powers can be done with floats.
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RE: nth root

[Tim Roberts]

Paul,
 
Yes, very good, on all counts.  Many thanks.
 
Tim
 



From: Paul Rubin [mailto:"http://phr.cx"@NOSPAM.invalid]
Sent: Sun 01-Feb-09 3:53 PM
To: python-list@python.org
Subject: Re: nth root



"Tim Roberts"  writes:
> Actually, all I'm interested in is whether the 100 digit numbers
> have an exact integral root, or not.  At the moment, because of
> accuracy concerns, I'm doing something like
> 
> for root in powersp:
> nroot = round(bignum**(1.0/root))
> if bignum==long(nroot)**root:
>  .
> which is probably very inefficient, but I can't see anything better.

First of all, convert the bignum to a float outside of the loop.  Second, 
precompute
the inverses 1.0/2.0, 1.0/3.0,   Third, do the exponentiation and 
comparison only
if the float equivalent is very close.  I bet almost all the time you're 
spending is
in bignum to float conversion.

The article

 Daniel J. Bernstein (1998). "Detecting perfect powers in essentially
 linear time". Mathematics of Computation 67 (223): 1253-1283
 (http://cr.yp.to/papers/powers-ams.pdf)

may be of interest.
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Re: Searching a file for multiple strings (PS)

[John Machin]

On Feb 1, 3:39 pm, Shawn Milochik  wrote:

> Not to discourage the use of Python, but it seems that fgrep with the
> -f flag already does exactly what you want. If you're on Windows, you
> can get the Windows version of fgrep here: http://unxutils.sourceforge.net/

That URL is antique and a dead end. When you find the actual
sourceforge project page (http://sourceforge.net/projects/unxutils/)
and browse the forums and the CVS repository, you'll see tumbleweed
blowing down Main Street and not much else (besides a few whinges
about that dead end URL, and many unanswered issues).

Alternative: http://gnuwin32.sourceforge.net/
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Re: nth root

[Paul Rubin]

"Tim Roberts"  writes:
> Actually, all I'm interested in is whether the 100 digit numbers
> have an exact integral root, or not.  At the moment, because of
> accuracy concerns, I'm doing something like
>  
> for root in powersp:
> nroot = round(bignum**(1.0/root))
> if bignum==long(nroot)**root:
>  .
> which is probably very inefficient, but I can't see anything better.

First of all, convert the bignum to a float outside of the loop.  Second, 
precompute
the inverses 1.0/2.0, 1.0/3.0,   Third, do the exponentiation and 
comparison only
if the float equivalent is very close.  I bet almost all the time you're 
spending is
in bignum to float conversion.

The article

 Daniel J. Bernstein (1998). "Detecting perfect powers in essentially
 linear time". Mathematics of Computation 67 (223): 1253-1283
 (http://cr.yp.to/papers/powers-ams.pdf)

may be of interest.
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Embedding numpy works once, but not twice??

[Deepak Chandran]

I have a program in which I have successfully embedded Python. Now, I want
to include NumPy as well (and other modules). I am able to import numpy
once. Then I close the python console in my program and then re-open it.
When I try to import numpy for a second time, the program crashes. Below is
a simple version of the problem.

The main() import numpy twice. The first import works fine -- prints "no
errors.". But the second load crashes the program. What is going on here?

By the way, this is all in Windows (XP and Vista have same problem) using
python25.dll (since numpy does not work for python26.dll). I am using MinGW
compiler.

#include 
#include 
#include 

int load(char * code)
{
PyObject *errobj, *errdata, *errtraceback, *pystring;
int retval;

   Py_Initialize();

PyObject *main = PyImport_AddModule("__main__");
PyObject* main_dict = PyModule_GetDict( main );

PyObject * rstring = PyRun_String( code, Py_file_input, main_dict, main_dict
); //the second main_dict was my_program_dict originally
 PyErr_Fetch (&errobj, &errdata, &errtraceback);
 if (errdata != NULL)
{
PyObject *s = PyObject_Str(errdata);
char * c = PyString_AS_STRING(s);
printf("%s\n",c);   //print any errors
Py_DECREF(s);
}
else
{
printf("no errors.\n");
 }
 Py_XDECREF(errobj);
Py_XDECREF(errdata);
Py_XDECREF(errtraceback);

Py_Finalize();
return 0;
}

int main()
{
load("import numpy\n");
load("import numpy\n");
}

//output is:
// no errors
// 
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RE: nth root

[Tim Roberts]

Actually, all I'm interested in is whether the 100 digit numbers have an exact 
integral root, or not.  At the moment, because of accuracy concerns, I'm doing 
something like
 
for root in powersp:
nroot = round(bignum**(1.0/root))
if bignum==long(nroot)**root:
 .
which is probably very inefficient, but I can't see anything better.
 
Tim
 
 
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Re: Searching a file for multiple strings (PS)

[Shawn Milochik]

On Sat, Jan 31, 2009 at 3:00 PM, Tim Chase
 wrote:
>>> I'm fairly new with python and am trying to build a fairly simple
>>> search script.  Ultimately, I'm wanting to search a directory of files
>>> for multiple user inputted keywords.  I've already written a script
>>> that can search for a single string through multiple files, now I just
>>> need to adapt it to multiple strings.
>

Not to discourage the use of Python, but it seems that fgrep with the
-f flag already does exactly what you want. If you're on Windows, you
can get the Windows version of fgrep here:
http://unxutils.sourceforge.net/

Shawn
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Re: is python Object oriented??

[David Bolen]

thmpsn@gmail.com writes:

> I don't know how you would do it in C# (or Java for that matter).
>
> In C++ you can play with pointers to "get at" some memory location
> somewhere in the object. The only portable way to know the exact
> location between the beginning of the object and the desired member is
> the offsetof() macro, but as I understand it this only works for POD
> types, which means that it won't work for classes such as:
>
> class NonPOD
> {
> private:
> int a;
> int b;
> public:
> NonPOD();
> ~NonPOD();
> int C();
> };
>
> (I haven't ever actually tried it, so I'm not sure.)
>
> Nevertheless, you can play and hope for the best. For example, if the
> member you want to get at is 'b', then you can do:
>
> NonPOD obj;
> std::cout << "obj.b = " << *(int*) ((unsigned char*) &obj + sizeof
> (int)) << std::endl;
>
> and hope that the compiler didn't leave a hole between the 'a' member
> and the 'b' member.

Probably moving off topic, but I don't think you have to get anywhere
near that extreme in terms of pointers, unless you're trying to deal
with instances for which you have no source but only opaque pointers.

I haven't gotten stuck having to do this myself yet, but I believe one
commmon "hack" for the sort of class you show above is to just
"#define private public" before including the header file containing
the class definition.  No fiddling with pointers, offsets, or
whatever, just normal object access syntax past that point.

Of course, I believe such a redefinition violates the letter of the
C++ standard, but most preprocessors do it anyway.  Also, it won't
handle the case where the "private:" is not used, but the members are
just declared prior to any other definition, since a class is private
by default.

But even then, if you had to, just make a copy of the class definition
(or heck, just define a structure if it's just data elements), ensure
the private portions are public, and then cast a pointer to the old
class instance to one of your new class instance.  Assuming you're
building everything in a single compiler, the layouts should match
just fine.  Again, normal object member access, no casting or pointers
needed (beyond the initial overall object pointer cast).

-- David
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Re: importlib: what is it, and why is it important?

[Benjamin Peterson]

excord80  gmail.com> writes:

> 
> Regarding this blog post:
http://sayspy.blogspot.com/2009/01/importlib-is-now-in-python-31.html

Brett has made many other blog posts about his work on importlib. You might try
examining those.

> 
> So, could someone explain what importlib exactly is, and why this new
> version that will be in Python 3.1 is significant? Will the import
> statement work differently in 3.1, and if so, in what way?

Basically importlib is all of the complicated logic in the import statment
written in Python. The point is to make importing more extensible and easier to
change.

The behavior of the import statement shouldn't be any different or that is a 
bug.




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importlib: what is it, and why is it important?

[excord80]

Regarding this blog post: 
http://sayspy.blogspot.com/2009/01/importlib-is-now-in-python-31.html

When I use the ``import foo`` statement at the top of my program, I
get a module imported. python has a search path it follows, finds the
module, and makes it available to my program. Works nice. :)

So, could someone explain what importlib exactly is, and why this new
version that will be in Python 3.1 is significant? Will the import
statement work differently in 3.1, and if so, in what way?
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Re: Tutorial on working with Excel files in Python (without COM and cross platform!) at PyConUS 2009

[Glenn Linderman]

On approximately 1/27/2009 5:19 PM, came the following characters from 
the keyboard of Chris Withers:

Hi All,

Too many people in the Python community think the only way to work with
Excel files in Python is using COM on Windows.

To try and correct this, I'm giving a tutorial at this year's PyCon in
Chicago on Wednesday, 25th March that will cover working with Excel
files in Python using the pure-python libraries xlrd, xlwt and xlutils.

I'll be looking to cover:

- Reading Excel Files

  Including formatting, unicode dates and formulae.

- Writing Excel Files

  Including formatting with easyxf and things like freeze pains, print
  areas, etc

- Filtering Excel Files

  A run through on the structure of xlutils.filter and some examples to
  show you how it works.

- Workshop for your problems

  I'm hoping anyone who attends will get a lot out of this! If you're
  planning on attending and have a particular problem you'd like to work
  on in this part of the tutorial, please drop me an email and I'll try
  and make sure I come prepared!

All you need for the tutorial is a working knowledge of Excel and
Python, with a laptop as an added benefit, and to be at PyCon this year:

http://us.pycon.org

I look forward to seeing you all there!



Good luck with the tutorial.  I can't use xlrd because it doesn't 
support comments.  So I use Open Office basic macros to transform the 
data into a usable form.  At least it is way faster than COM, and 
(although I'm using Windows) I think it could be done on Linux.


--
Glenn -- http://nevcal.com/
===
A protocol is complete when there is nothing left to remove.
-- Stuart Cheshire, Apple Computer, regarding Zero Configuration Networking
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Re: is python Object oriented??

[Michael Torrie]

thmpsn@gmail.com wrote:
> More interestingly, though, most compilers translate C and C++ code to
> assembler first. Does that mean that you can do object-oriented
> programming, generic programming, and procedural programming in
> assembler?
>
> Answer: No, but you can probably -- very clumsily -- fake them.)

This is getting quite far off the topic, but of course you can, and it's
not faking anything.  This should be obvious.

You can certainly do OO programming in C, which is a glorified
assembler.  For example, the gobject system defines a complete
object-oriented system with classes, inheritance, polymorphism,
encapuslation.  It uses structures for encapsulating the data and call
tables for virtual methods (to use a c++ parlance).  It's such a well
defined object model that you can, with gtkmm, even extend a c-based
gobject class with C++!  Of course you can also extend gobject-based C
classes with python as well using PyBank to import them.

Back when assembly was still somewhat in vogue I read a book on
programming assembly in an object-oriented manner.  So of course you
can.   Yes it can be clumsy without syntactic sugar.  If you set up call
tables, you can handle polymorphism.  How would this be faking it?  By
your definition C++ is faking it since C++ compiles to assembly.  In the
early days, C++ was first implemented as a preprocessor that emitted
straight C code.  And I guess python fakes it since the python
interpreter is implemented in C compiled to ASM.

Maybe the terminology would be less confusing if we considered the
terms, object-oriented programming, object-oriented languages,
object-oriented systems.  Any language can be used for the first.
Python, Java, C++ can be defined by the second, and things like Python
(the runtime environment), .NET, JVM, Parrot, can be defined by the last
term.  Fair enough?

Python is certainly an object-oriented language, and implements a
complete object-oriented system.  Python can support coding in an
object-oriented methodology, or you can code traditionally while still
taking advantage of the complete OO system.
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Re: Does the Python community really follow the philospy of "Community Matters?"

[r]

On Jan 31, 7:24 pm, John Machin  wrote:
> A most munificent malapropism! Sherman's goat must be serene with
> entropy!!

Who say's George Bush did't have anything to offer :). He was the
decider after all.
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Re: help me python

[Robert Kern]

On 2009-01-31 19:52, John Machin wrote:

On Feb 1, 11:09 am, andrew cooke  wrote:

On Jan 31, 5:36 pm, aolsu...@gmail.com wrote:


C:\Python26>vnc.py
Traceback (most recent call last):
   File "C:\Python26\vnc.py", line 4, in
 import PyD3DES
ImportError: DLL load failed: The specified module could not be found.

i'm surprised no-one has replied here.  what is happening is that the
vnc module is trying to load a library it needs, called PyD3DES (this
is a compiled library, a ".dll", not python source).  a little
googling shows that this is part of the vnc package.

so either the vnc package is not installed correctly, or you have a
problem with paths.


File "C:\Python26\vnc.py" doesn't look like correct installation to
me.

My Googling found vnc.py here:
http://www.darkc0de.com/others/vnc.py

This appears to be a hack/crack site ... should we be helping the OP
with this?


It's actually just part of PyVNC, a perfectly legitimate VNC client:

  http://bdash.net.nz/svn/projects/PyVNC/

--
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco

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Re: Where to host a (Python) project?

[Roy H. Han]

I really like WebFaction for web-based Python projects.  It's a paid
web-hosting service, though.  What I like is how they always have the
most up-to-date Python packages and frameworks using one-click
installers.

On Sat, Jan 31, 2009 at 4:30 PM, andrew cooke  wrote:
> On Jan 31, 4:50 pm, "Giampaolo Rodola'"  wrote:
>> Google Code.
>>
>> --- Giampaolohttp://code.google.com/p/pyftpdlib
>
> thanks - that's a nice example.  i'm a bit concerned about the whole
> google corporation thing, but reading through the ideological check-
> sheet at savannah convinced me i wasn't worthy and your project looks
> good (i admit i haven't seen that many google projects, but they all
> seemed abandoned/bare/hostile).  so i'll follow the majority here and
> give google code a go.
>
> cheers,
> andrew
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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Re: help me python

[John Machin]

On Feb 1, 11:09 am, andrew cooke  wrote:
> On Jan 31, 5:36 pm, aolsu...@gmail.com wrote:
>
> > C:\Python26>vnc.py
> > Traceback (most recent call last):
> >   File "C:\Python26\vnc.py", line 4, in 
> >     import PyD3DES
> > ImportError: DLL load failed: The specified module could not be found.
>
> i'm surprised no-one has replied here.  what is happening is that the
> vnc module is trying to load a library it needs, called PyD3DES (this
> is a compiled library, a ".dll", not python source).  a little
> googling shows that this is part of the vnc package.
>
> so either the vnc package is not installed correctly, or you have a
> problem with paths.

File "C:\Python26\vnc.py" doesn't look like correct installation to
me.

My Googling found vnc.py here:
http://www.darkc0de.com/others/vnc.py

This appears to be a hack/crack site ... should we be helping the OP
with this?
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Re: Where to host a (Python) project?

[Jesse Noller]

On Sat, Jan 31, 2009 at 4:30 PM, andrew cooke  wrote:
> On Jan 31, 4:50 pm, "Giampaolo Rodola'"  wrote:
>> Google Code.
>>
>> --- Giampaolohttp://code.google.com/p/pyftpdlib
>
> thanks - that's a nice example.  i'm a bit concerned about the whole
> google corporation thing, but reading through the ideological check-
> sheet at savannah convinced me i wasn't worthy and your project looks
> good (i admit i haven't seen that many google projects, but they all
> seemed abandoned/bare/hostile).  so i'll follow the majority here and
> give google code a go.
>
> cheers,
> andrew
> --
> http://mail.python.org/mailman/listinfo/python-list
>

Bitbucket: http://bitbucket.org/ (I use this, move from google code)
Github: http://github.com/
Launchapd: https://launchpad.net/
FreeHG: http://freehg.org/

Google is nice due to the groups/mailing list options, but I find I
don't miss mailing lists all that much after being subscribed to so
many.

-jesse
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Re: Import Replacement

[Gabriel Genellina]

En Sat, 31 Jan 2009 18:22:54 -0200, Gary Herron  
 escribió:



James Pruitt wrote:

Imagine there are two files horse.py and buffalo.py. horse.py is
imported by another file rider.py. Is it possible to make it so that
under certain circumstances possibly based on an environment variable
or something similar that when rider.py imports horse.py, it actually
imports buffalo.py sort of like a behind the scenes replacement so
that rider.py needs little, preferably absolutely no modification?


If horse and buffalo have the same interface then try something like  
this:


if ...:
  import horse as ridable
else:
  import buffalo as ridable
# Now use ridable as any module...

If each defines a class of its own name, but the classes have identical
interfaces, then try

if ...:
  from horse import Horse as Ridable
else:
  from buffalo import Buffalo as Ridable
# Then instantiate
animal = Ridable(...)


Another alternative, that does not involve changing rider.py, would be to  
rename horse.py -> _horse.py, buffalo.py -> _buffalo.py and write a *new*  
horse.py:


if ...:
  from _horse import *
else:
  from _buffalo import *

Then, rider.py (and all other modules) still says "import horse", but it  
will get one or another depending on the condition.


--
Gabriel Genellina

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Re: install modules for specific python version

[John Machin]

On Feb 1, 12:00 pm, Brendan Miller  wrote:
> -BEGIN PGP SIGNED MESSAGE-

> I have several version of python running side by side on my ubuntu
> install (2.5,2.6,3.0).
>
> I'm installing a module with a setup.py script, in this case
> logilab-common, so that I can get pylint going. However, I need to
> install into python 2.6, but by default it picks out 2.5 and throws
> things in the site packages for that version.
>
> Is there a standard way to specify what version of python you want to
> install into?

Quite generally, if you want to install a module into Python X.Y, use
Python X.Y to run the setup.py script.

E.g. on Windows I'd do
directory-containing-setup.py> c:\python26\python setup.py install

Just do the equivalent on ubuntu.

Cheers,
John
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Re: install modules for specific python version

[Robert Kern]

On 2009-01-31 19:00, Brendan Miller wrote:

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

I have several version of python running side by side on my ubuntu
install (2.5,2.6,3.0).

I'm installing a module with a setup.py script, in this case
logilab-common, so that I can get pylint going. However, I need to
install into python 2.6, but by default it picks out 2.5 and throws
things in the site packages for that version.

Is there a standard way to specify what version of python you want to
install into? I originally installed my other python versions with the
altinstall method.


Whichever python executable that you used to run the setup.py is the version 
that the package gets installed to. Most likely, you will want to do something 
like this:


  $ python2.6 setup.py install

--
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco

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install modules for specific python version

[Brendan Miller]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

I have several version of python running side by side on my ubuntu
install (2.5,2.6,3.0).

I'm installing a module with a setup.py script, in this case
logilab-common, so that I can get pylint going. However, I need to
install into python 2.6, but by default it picks out 2.5 and throws
things in the site packages for that version.

Is there a standard way to specify what version of python you want to
install into? I originally installed my other python versions with the
altinstall method.
-BEGIN PGP SIGNATURE-
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iEYEARECAAYFAkmE9BIACgkQ4eGWG/zYzOmmdgCfbjr3p3wQ8A0TpjeFaPJtmHkx
ktQAoI7wONrj5gT4BDclePpwY5kiCy8p
=Pg9L
-END PGP SIGNATURE-
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Re: receive and react to MIDI input

[r]

Sorry i gave you the wrong module, try PMIDI for python 2.5
(win32.exe):
http://sourceforge.net/project/showfiles.php?group_id=65529&package_id=106729

Also try this page near the bottom under "MIDI Mania" for more
http://wiki.python.org/moin/PythonInMusic
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Re: Newbie Question: Can't multiply sequence by non-int of type 'str'

[Paulo Repreza]

Hi,

Thanks for your reply. It worked.

Paulo Repreza

On Sat, Jan 31, 2009 at 4:25 PM, Robert Kern  wrote:

> On 2009-01-31 18:19, Paulo Repreza wrote:
>
>> Hi,
>> I'm just learning the very basics of python and I ran into this problem
>> in version 3.0/3000:
>>  >>>x = input("x: ")
>> x: 36
>>  >>> y = input("y: ")
>> y: 42
>>  >>> print (x*y)
>> Traceback (most recent call last):
>> File "", line 1, in 
>> print (x*y)
>> TypeError: can't multiply sequence by non-int of type 'str'
>> But when I run the same code with Python 2.6.1 it does prints the result.
>>
>
> In Python 3.0, the 2.x input() function, which evaluates the string, was
> removed, and the 2.x raw_input() function, which just returns the string
> that was entered, was renamed to input().
>
> Is there any special function that I should add in order to work
>> properly under Python 3.0?
>>
>
> x = int(input('x: '))
> y = int(input('y: '))
>
> --
> Robert Kern
>
> "I have come to believe that the whole world is an enigma, a harmless
> enigma
>  that is made terrible by our own mad attempt to interpret it as though it
> had
>  an underlying truth."
>  -- Umberto Eco
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
--
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Re: Newbie Question: Can't multiply sequence by non-int of type 'str'

[Robert Kern]

On 2009-01-31 18:19, Paulo Repreza wrote:

Hi,
I'm just learning the very basics of python and I ran into this problem
in version 3.0/3000:
 >>>x = input("x: ")
x: 36
 >>> y = input("y: ")
y: 42
 >>> print (x*y)
Traceback (most recent call last):
File "", line 1, in 
print (x*y)
TypeError: can't multiply sequence by non-int of type 'str'
But when I run the same code with Python 2.6.1 it does prints the result.


In Python 3.0, the 2.x input() function, which evaluates the string, was 
removed, and the 2.x raw_input() function, which just returns the string that 
was entered, was renamed to input().



Is there any special function that I should add in order to work
properly under Python 3.0?


x = int(input('x: '))
y = int(input('y: '))

--
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco

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Re: Does the Python community really follow the philospy of "Community Matters?"

[r]

On Jan 30, 4:36 pm, Steve Holden  wrote:
[snip]
> It's mostly a matter of teaching by example. I'd like to think I usually
> set a good example, but I've certainly been known to get crabby from time
> to time

Steve you are defiantly the better of two evils around here :D
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Newbie Question: Can't multiply sequence by non-int of type 'str'

[Paulo Repreza]

Hi,

I'm just learning the very basics of python and I ran into this problem in
version 3.0/3000:

>>>x = input("x: ")
x: 36
>>> y = input("y: ")
y: 42
>>> print (x*y)
Traceback (most recent call last):
  File "", line 1, in 
print (x*y)
TypeError: can't multiply sequence by non-int of type 'str'

But when I run the same code with Python 2.6.1 it does prints the result.

Is there any special function that I should add in order to work properly
under Python 3.0?

Thanks,

Paulo Repreza
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Re: help me python

[andrew cooke]

On Jan 31, 5:36 pm, aolsu...@gmail.com wrote:
> C:\Python26>vnc.py
> Traceback (most recent call last):
>   File "C:\Python26\vnc.py", line 4, in 
>     import PyD3DES
> ImportError: DLL load failed: The specified module could not be found.

i'm surprised no-one has replied here.  what is happening is that the
vnc module is trying to load a library it needs, called PyD3DES (this
is a compiled library, a ".dll", not python source).  a little
googling shows that this is part of the vnc package.

so either the vnc package is not installed correctly, or you have a
problem with paths.

since you are using windows i can't help you in any more detail than
that - hope it helps.

andrew
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Re: nth root

[Tim Roberts]

"Tim Roberts"  wrote:
> 
>Thanks - you're probably right - just my intuition said to me that rather than 
>calculating that the 13th root of 
>4021503534212915433093809093996098953996019232
>is 3221.2904208350265
>there must be a quicker way of finding out its between 3221 and 3222
> 
>but perhaps not.

Also, remember that the number you computed there is not really the 13th
root of 4021503534212915433093809093996098953996019232.  When you convert
it to float to do the exponentiation, you're losing everything after the
15th significant digit.  Of course, if all you're looking for is the
nearest integer, that's not very relevant.

Do you really need the absolute number?  You could take log(x)/13 and work
with the log of the results.  I suspect (without trying it) that's faster
than the exponentiation.

>From one Tim Roberts to another.
-- 
Tim Roberts, t...@probo.com
Providenza & Boekelheide, Inc.
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Re: nth root

[Robert Kern]

On 2009-01-30 22:00, Tim Roberts wrote:

Unfortunately, unless I'm doing something wrong, this appears to take 20 times 
as long... :-)

What on earth are numpy and psyco?  Do I need to watch the Lord of the Rings?


No, but Google would help.

--
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco

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Re: persistent TCP connection in python using socketserver

[Stephen Hansen]

Cheers mate I had a look into twisted but was put off by the FAQ
stating 1.0+ modules may or may not be stable, and only the 'core' is.
I don't wanna be messing around with a potentially buggy server, so im
gonna roll my own using the sockets module.
You didn't read that FAQ right: its addressing API stability. Meaning,"Are you going to keep this API next release or is it gonna change?"With your description of what you're doing, I'd be very surprised if youneeded to wander near an unstable/experimental module with a stillshifting API.Twisted is VERY stable.--S



signature.asc
Description: OpenPGP digital signature
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Re: is python Object oriented??

[thmpsn . m . k]

On Jan 31, 2:27 pm, Christian Heimes  wrote:
> thmpsn@gmail.com schrieb:
>
> > But it's only a faking, and things such as inheritance and
> > polymorphism are implemented clumsily (actually I'm not even sure
> > about polymorphism). And of course, there are still no private
> > members.
>
> Do you honestly believe that C++'s private members are really private?
> Privateness is only enforced during parsing time. Nobody can stop you
> from messing around with header files or memory. You can still access
> and modify private members but it's all messy and ugly. Even C# and .NET
> don't stop you from doing nasty things from unmananged assemblies.

I don't know how you would do it in C# (or Java for that matter).

In C++ you can play with pointers to "get at" some memory location
somewhere in the object. The only portable way to know the exact
location between the beginning of the object and the desired member is
the offsetof() macro, but as I understand it this only works for POD
types, which means that it won't work for classes such as:

class NonPOD
{
private:
int a;
int b;
public:
NonPOD();
~NonPOD();
int C();
};

(I haven't ever actually tried it, so I'm not sure.)

Nevertheless, you can play and hope for the best. For example, if the
member you want to get at is 'b', then you can do:

NonPOD obj;
std::cout << "obj.b = " << *(int*) ((unsigned char*) &obj + sizeof
(int)) << std::endl;

and hope that the compiler didn't leave a hole between the 'a' member
and the 'b' member.

Getting at the 'a' member would be easier because the first member of
a struct/class always has the same memory location as the object
itself (although again I'm not sure if this is true for non-POD types
as well).

So: Sometimes it may work, usually it will be unsafe and/or non-
portable, and in most cases the procedure will look complicated. It
certainly isn't something I'd try in a real application. However, it
WOULD be tempting to access the member if the language allows me to
just write:

print "obj.b =", obj.b

and be done with it.

Personally, in Python, I use double underscores for "private" members,
so the above would look like:

print "obj.b =", obj._NonPOD__b

but it's still easier than the C++ example.

> Seriously, 'private' and 'protected' are merely tools to stop bad
> programmers from doing bad stuff. And the serve as documentation, too.

It's not just documentation. For example, suppose you're reading a
class definition and see the declaration of a veryInterestingMember
and forget that you're not supposed to access it. If you try to access
it, the compiler will give you a diagnostic message at compile time.

So you can think of it as an error-checking tool as well.

> Oh, by the way, the first C++ compilers just converted C++ code to C
> code. Such much about "You can't do OOP in C."!

More interestingly, though, most compilers translate C and C++ code to
assembler first. Does that mean that you can do object-oriented
programming, generic programming, and procedural programming in
assembler?

(Answer: No, but you can probably -- very clumsily -- fake them.)


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Re: Tkinter w.pack()?

[Steve Holden]

W. eWatson wrote:
> Steve Holden wrote:
>> W. eWatson wrote:
>>> r wrote:
 On Jan 28, 10:12 pm, "W. eWatson"  wrote:
> Where in the world is a description of pack() for Tkinter widgets?
> Is it
> some sort of general method for all widgets? I'm looking in a few
> docs that
> use it without ever saying where it is described. For one,
> . In the NM Tech pdf on
> Tkinter,
> it's not found anywhere. I see Universal methods for widgets, but no
> mention
> of pack(). package, packed, but no pack.
 did you try here :)
 http://effbot.org/tkinterbook/pack.htm
>>> Thanks. I have the site bookmarked, but it's hard to search. I posted a
>>> comment to them that they should have it in pdf form.
>>>
>> http://letmegooglethatforyou.com/?q=site%3Aeffbot.org%2Ftkinterbook+pack
>>
>> regards
>>  Steve
> Well, that's an interesting "link". Another side of Google facilities?
> Maybe you're using Snagit or its brethern? However, I'm interested in
> searching a pdf, which, of course, doesn't yet exist.
> 
OK, someone asked if you'd seen the HTML pages. You replied that you had
them bookmarked but they were difficult to search. So I simply
demonstrated that a search of the site for "pack" gave the right page as
its first result.

Maybe you *do* want a PDF, but it will be less searchable than the
existing HTML, so I am somewhat confused about why.

regards
 Steve
-- 
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Holden Web LLC  http://www.holdenweb.com/

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Re: SimpleXMLRPCServer question

[rdmurray]

Quoth flagg :
> Let me see if i can elaborate on the requirements.  I have 20+
> different zone files.  I want the xmlrpc server to be able to
> determine what zone file to open by looking at the incoming xml
> request.  For example one of the functions I have now is to show a DNS
> record (I am using dnspython for most of this work)
> 
> If i send an xmlrpc request that uses the 'showRecord' function with
> params of 'oracle1.foo.bar.com'  I want to parse the "params" piece
> and then instruct the xml-rpc server to open foo.bar.com.zone for
> reading.  The reason why i was looking at do_Post() and _dispatch was
> to attempt to read the incoming params and do exactly that.
> 
> Do you think there is an easier way of accomplishing this, than the
> way I am going about it?

Yeah.  Take a look at the SimpleXLMRPC documentation:

http://docs.python.org/library/simplexmlrpcserver.html

In addition to setting up the server as instructed (let's assume you
assign it to the variable 'server'), you just need to do something like:

class MyFunctions:

def showRecord(self, dnsname):
domain = '.'.join(dnsname.split('.')[1:])
with open(domain+'.zone')) as myfile:
# do stuff with data from myfile

server.register_instance(MyFunctions())


You would modify the body of that function to meet your processing
requirements, of course.  That is, SimpleXMLRPCServer does the request
parsing for you, calls the correspondingly named method, and passes it
the params as method arguments.

(This example is taken from the SimpleXMLRPC documentation, I just
selected one particular way of exposing the methods: via a class
instance).

--RDM

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Re: is python Object oriented??

[Michael Torrie]

Steve Holden wrote:
> You can think what you like, but there is a fundamental difference
> between methods of a class and functions of a module. Until you
> appreciate that you will likely make mistakes. Don't worry, though, we
> all learn from our mistakes.

And this fundamental difference is?

>From what I can tell an instance method is an object that encapsulates
the function object in a closure that makes sure it has a reference to
"self."  I know that you dynamically add functions to objects creating
methods dynamically, by using new.instancemethod or something.

This seems to indicate to me that there are functions and there are
functions.  Methods are in fact functions, just with a callable wrapper
around them.  Is this not so?
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Re: is python Object oriented??

[Michael Torrie]

thmpsn@gmail.com wrote:
>> To be clear, python does not force you to lay out your code according to
>> some strict object-oriented paradigm.  But Python itself is still purely
>> object-oriented, as is your script when parsed.
>
> But it's only a faking, and things such as inheritance and
> polymorphism are implemented clumsily (actually I'm not even sure
> about polymorphism). And of course, there are still no private
> members.

How is it faking?  The class of a function object is "function," which
is of the metaclass "type."  What more do you want?  If Guido himself
declared that functions are objects would you believe that?  Or modules?

Since a function object is an instance of the class "function" I don't
see how you could inherit from it, and polymorphism has nothing to do
with this either.  Maybe what you are talking about is deriving a class
from the class "function."  Not sure if that's allowed, mainly because
the language has defined a standard way of declaring a function (methods
are functions too, of course), so creating a useful, derived function
object would be difficult given how the syntax of the language works.

Private members?  I could stick add any attribute I wanted to a function
object and ask that people treat it as private if I wanted to:

def myfunc():
pass

myfunc.__dict__['_private'] = 4

If you are insinuating that not forcing private attributes to be
unaccessible by others (black box theory) is in somehow a violation of
object-oriented semantics, think again.  It's not.  (There are no formal
definitions of OO anyay, but wikipedia lists quite a few characteristics
considered common to OO, and enforced private members is not one of them.)
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Re: is python Object oriented??

[Michael Torrie]

thmpsn@gmail.com wrote
>> This allows people to meddle with internals, at their own risk,
>> if it ends up being absolutely necessary.
> 
> If it ends up being necessary, the class's design is flawed. (Though
> in this case, the flaw is easily solved by simply providing a getter.)

No the class design is not necessarily flawed.  Sometimes it is
desirable to modify a class's behavior at a lower level.  In Java this
isn't possible directly and so it has led to an entire class of
libraries that provide means of doing this.  For more information, look
up "Aspect-oriented Programming" on wikipedia.  Since most
aspect-oriented programming examples I've seen are in Java I never
understood much about it ("cross-cutting concerns" is a pretty
meaningless explanation) until I realized that metaprogramming in
python, monkey-patching classes, and dynamically adding attributes to an
existing class are all forms of aspect-oriented programming.  And it
turns out to be quite useful for some things.

One area where aspect-oriented programming is useful is in libraries
that add security layers to objects and methods.  Rather than having to
make code directly aware of the security layer (which could take
different forms), we can instead reach into the classes and, for
example, wrap certain methods in a function that enforces security.  If
we do it in the class directly, then even code that descends from this
class will transparently "inherit" all of the newly added security layer
code that was never there when the code was first written.  By security
layer I'm talking more about code that enforces certain user
authentication before use (as in web programming) rather than "secure" code.
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Re: Where to host a (Python) project?

[andrew cooke]

On Jan 31, 4:50 pm, "Giampaolo Rodola'"  wrote:
> Google Code.
>
> --- Giampaolohttp://code.google.com/p/pyftpdlib

thanks - that's a nice example.  i'm a bit concerned about the whole
google corporation thing, but reading through the ideological check-
sheet at savannah convinced me i wasn't worthy and your project looks
good (i admit i haven't seen that many google projects, but they all
seemed abandoned/bare/hostile).  so i'll follow the majority here and
give google code a go.

cheers,
andrew
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help me python

[aolsuppo]

C:\Python26>vnc.py
Traceback (most recent call last):
  File "C:\Python26\vnc.py", line 4, in 
import PyD3DES
ImportError: DLL load failed: The specified module could not be found.
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Re: is python Object oriented??

[Christian Heimes]

thmpsn@gmail.com schrieb:
> But it's only a faking, and things such as inheritance and
> polymorphism are implemented clumsily (actually I'm not even sure
> about polymorphism). And of course, there are still no private
> members.

Do you honestly believe that C++'s private members are really private?
Privateness is only enforced during parsing time. Nobody can stop you
from messing around with header files or memory. You can still access
and modify private members but it's all messy and ugly. Even C# and .NET
don't stop you from doing nasty things from unmananged assemblies.

Seriously, 'private' and 'protected' are merely tools to stop bad
programmers from doing bad stuff. And the serve as documentation, too.

Oh, by the way, the first C++ compilers just converted C++ code to C
code. Such much about "You can't do OOP in C."!

Christian

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Re: Import Replacement

[Gary Herron]

James Pruitt wrote:
> Imagine there are two files horse.py and buffalo.py. horse.py is
> imported by another file rider.py. Is it possible to make it so that
> under certain circumstances possibly based on an environment variable
> or something similar that when rider.py imports horse.py, it actually
> imports buffalo.py sort of like a behind the scenes replacement so
> that rider.py needs little, preferably absolutely no modification?
> Right now, I am investigating the use of sys.modules and doing
> something using sys.modules['horse.py'] = 'buffalo.py'.
> 
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>   

If horse and buffalo have the same interface then try something like this:

if ...:
  import horse as ridable
else:
  import buffalo as ridable
# Now use ridable as any module...

If each defines a class of its own name, but the classes have identical
interfaces, then try

if ...:
  from horse import Horse as Ridable
else:
  from buffalo import Buffalo as Ridable
# Then instantiate
animal = Ridable(...)



Gary Herron

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Re: Where to host a (Python) project?

[Andrey Demidov]

I use Google Code.
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Re: SimpleXMLRPCServer question

[flagg]

On Jan 30, 8:12 pm, rdmur...@bitdance.com wrote:
> Quoth flagg :
>
> > I am working on a very basic xmlrpc server, which will expose certain
> > functions for administering BIND zone files.  The big problem I am
> > having is parsing the incoming xmlrpc request.  Basically part of the
> > xmlrpc request will help deterime which zone file is edited.    I have
> > been looking at the do_POST() method from SimpleXMLRPCDispatcher and
> > it seems like I could code something which overides that method,
> > however I am new to programming am at a loss, i might even be making
> > this tougher than it needs to be.   Is there a way to parse the
> > incoming xmlrpc request before the function it is calling is executed?
>
> Wouldn't you be overriding '_dispatch' on SimpleXMLRPCServer instead?
>
> It's been a while since I looked at XMLRPC, but why wouldn't you have
> a operation names, with the zone file to operate on as an argument?
> Then you'd just be defining your operations as methods on your
> SimpleXMLRPCServer, and they'd use the argument to determine which file
> to operate on.
>
> If that doesn't make sense, either I've forgotten how XMLRPC works,
> or you should explain your requirements a bit more.
>
> --RDM

Let me see if i can elaborate on the requirements.  I have 20+
different zone files.  I want the xmlrpc server to be able to
determine what zone file to open by looking at the incoming xml
request.  For example one of the functions I have now is to show a DNS
record (I am using dnspython for most of this work)

If i send an xmlrpc request that uses the 'showRecord' function with
params of 'oracle1.foo.bar.com'  I want to parse the "params" piece
and then instruct the xml-rpc server to open foo.bar.com.zone for
reading.  The reason why i was looking at do_Post() and _dispatch was
to attempt to read the incoming params and do exactly that.

Do you think there is an easier way of accomplishing this, than the
way I am going about it?
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Re: nth root

[Mark Dickinson]

On Jan 31, 7:04 pm, ajaksu  wrote:
> also a great way make some innocent bystander waste his eyesight
> trying to figure out the magic trick :D

Oh, come on!  At least I put the two lines next to each other!  :-)

Mark

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Re: Searching a file for multiple strings (PS)

[Tim Chase]

I'm fairly new with python and am trying to build a fairly simple
search script.  Ultimately, I'm wanting to search a directory of files
for multiple user inputted keywords.  I've already written a script
that can search for a single string through multiple files, now I just
need to adapt it to multiple strings.


One more item:  if your files are large, it may be more efficient 
to scan through them incrementally rather than reading the whole 
file into memory, assuming your patterns aren't multi-line (and 
by your escaping example, I suspect they're just single-words):


  items = set(['a', 'b', 'c'])
  for fname in ['file1.txt', 'file2.txt']:
still_to_find = items.copy()
for line in file(fname):
  found = set()
  for item in still_to_find:
if item in line:
  found.add(item)
  still_to_find.difference_update(found)
  if not still_to_find: break
if still_to_find:
  print "%s: Nope" % fname
else:
  print "%s: Yep" % fname

just one more way to do it :)

-tkc



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Re: Where to host a (Python) project?

[Giampaolo Rodola']

On 31 Gen, 12:46, andrew cooke  wrote:
> Hi,
>
> I have a new project, that I just released in beta 
> (http://www.acooke.org/lepl- a recursive decent parser with full
> backtracking).  At the moment I am using pypi and setuptools for
> distribution (it's a pure python package) and I am happy with hosting
> static web pages (the manual and api doc linked to above) on my own
> site (I did try the packages.python.org web pages, but it seemed
> pointless duplicating my own).
>
> However, i am thinking I could really do with:
> - a mailing list
> - simple bug tracking
> - subversion
> and am wondering which is the best (free) provider for these (the code
> is LGPL open source).  I'd prefer a mailing list to something like
> google groups (although I guess it may be possible to configure a
> gateway) and I could open up my personal subversion server, but that
> seems like a lot of work (not really that interested in moving to
> something other than svn).
>
> Any recommendations?
>
> Thanks,
> Andrew

Google Code.


--- Giampaolo
http://code.google.com/p/pyftpdlib
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Re: Searching a file for multiple strings

[Tim Chase]

I'm fairly new with python and am trying to build a fairly simple
search script.  Ultimately, I'm wanting to search a directory of files
for multiple user inputted keywords.  I've already written a script
that can search for a single string through multiple files, now I just
need to adapt it to multiple strings.

I found a bit of code that's a good start:

import re
test = open('something.txt', 'r').read()

list = ['a', 'b', 'c']

foundit = re.compile('|'.join(re.escape(target) for target in list))
if foundit.findall(test):
print 'yes!'

The only trouble with this is it returns yes! if it finds any of the
search items, and I only want a return when it finds all of them.  Is
there a bit of code that's similar that I can use?


[insert standard admonition about using "list" as a variable 
name, masking the built-in "list"]
Unless there's a reason to use regular expressions, you could 
simply use


  test = open("something.txt").read()
  items = ['a', 'b', 'c']
  if all(s in test for s in items):
print "Yes!"
  else:
print "Sorry, bub"

This presumes python2.5 in which the "all()" function was added. 
 Otherwise in pre-2.5, you could do


  for s in items:
if s not in test:
  print "Sorry, bub"
  break
  else:
print "Yeparoo"

(note that the "else" goes with the "for", not the "if")

-tkc





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Re: is python Object oriented??

[Andreas Waldenburger]

On Sat, 31 Jan 2009 09:11:03 +0100 Laszlo Nagy 
wrote:

> Python is not a pure object oriented language, because it has other 
> programming tools, for example functions.

I'm not sure about the first part of the sentence, but Python's
functions are objects. Check it in the interpreter: attributes,
methods, the whole caboodle.

regards,
/W

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Import Replacement

[James Pruitt]

Imagine there are two files horse.py and buffalo.py. horse.py is imported by
another file rider.py. Is it possible to make it so that under certain
circumstances possibly based on an environment variable or something similar
that when rider.py imports horse.py, it actually imports buffalo.py sort of
like a behind the scenes replacement so that rider.py needs little,
preferably absolutely no modification? Right now, I am investigating the use
of sys.modules and doing something using sys.modules['horse.py'] =
'buffalo.py'.
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Import Replacement

[James Pruitt]

Imagine there are two files horse.py and buffalo.py. horse.py is imported by
another file rider.py. Is it possible to make it so that under certain
circumstances possibly based on an environment variable or something similar
that when rider.py imports horse.py, it actually imports buffalo.py sort of
like a behind the scenes replacement so that rider.py needs little,
preferably absolutely no modification? Right now, I am investigating the use
of sys.modules and doing something using sys.modules['horse.py'] =
'buffalo.py'.
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Re: len()

[Andreas Waldenburger]

On Sat, 31 Jan 2009 13:27:02 -0500 Pat  wrote:

> Tobiah wrote:
> > Just out of curiosity, why was len() made to
> > be it's own function?  I often find myself
> > typing things like my_list.len before I
> > catch myself.
> > 
> > Thanks,
> > 
> > Toby
> 
> I'm surprised that no one responded to that question.
> 
Huh? Gabriel Genellina replied about 46 minutes after it was posted.
Might it be that your newsserver is a bit laggy?

regards
/W

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Searching a file for multiple strings

[gotbyrd]

Hello,

I'm fairly new with python and am trying to build a fairly simple
search script.  Ultimately, I'm wanting to search a directory of files
for multiple user inputted keywords.  I've already written a script
that can search for a single string through multiple files, now I just
need to adapt it to multiple strings.

I found a bit of code that's a good start:

import re
test = open('something.txt', 'r').read()

list = ['a', 'b', 'c']

foundit = re.compile('|'.join(re.escape(target) for target in list))
if foundit.findall(test):
print 'yes!'

The only trouble with this is it returns yes! if it finds any of the
search items, and I only want a return when it finds all of them.  Is
there a bit of code that's similar that I can use?

Thanks
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Re: Python-list Digest, Vol 64, Issue 697

[AJ Ostergaard]

AJ Ostergaard wrote:
I'm not suggesting it's not operating as advertised - I'm  
suggesting the

'advertising' is slightly sguiffy if you catch my drift. I guess it's
just me that finds it slightly counter intuitive. Surely  
intuitively the

expression is "and" and therefore should always return a boolean?

You might think so, and it wouldn't be an entirely unreasonable  
thought,

but in practice it makes a lot of sense to retain the original value
where possible.

The fact is that any left-hand operand that evaluates to false in a
Boolean context can be used as it stands rather than being converted  
to

Boolean first. So the conversion is essentially useless processing.


That's what I've figured out during the course of the day.

Thanks for listening one and all! :)

Regards,
AJ

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Re: search speed

[Tim Rowe]

2009/1/30 Scott David Daniels :

> Be careful with your assertion that a regex is faster, it is certainly
> not always true.

I was careful *not* to assert that a regex would be faster, merely
that it was *likely* to be in this case.


-- 
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Re: nth root

[ajaksu]

On Jan 31, 12:03 pm, Mark Dickinson  wrote:
[...]
> t1 = timeit.Timer("x = n**power", "n = 
> 4021503534212915433093809093996098953996019232; power = 1./13")
> t2 = timeit.Timer("x = n**power", "n = 
> 4021503534212915433093809093996098953996019232.; power = 1./13")

And by using a float literal instead of "float
(402150353421291543309...)", (BTW, here -^), it not only is faster but
also a great way make some innocent bystander waste his eyesight
trying to figure out the magic trick :D
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Re: Python Doc 2.6 vs 2.5--A Matter of Format?

[Martin v. Löwis]

> I see  for 2.5 and
>  for 2.6. I'm guessing these two pages differ
> somewhat in formats simply because someone decided to do so, and not
> that I'm in the wrong place for each of the two versions, correct?

Correct. The documentation format has significantly changed.

> For
> example, somewhere down in the 2.5, I should find the 2.6 equivalent of
> ?

Not necessarily. The change in format also means a change in indices;
the formats differ in what indices precisely are created, and what
precisely they contain. Try

http://www.python.org/doc/2.5/lib/genindex.html

Regards,
Martin
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Re: Empty string is False right?

[Scott David Daniels]

Steve Holden wrote:

AJ Ostergaard wrote:

I'm not suggesting it's not operating as advertised - I'm suggesting the
'advertising' is slightly sguiffy if you catch my drift. I guess it's
just me that finds it slightly counter intuitive. Surely intuitively the
expression is "and" and therefore should always return a boolean?

...

You might think so, and it wouldn't be an entirely unreasonable thought,
but in practice it makes a lot of sense to retain the original value
where possible.


For example:
print name_from_form or default_name
or:
main(sys.arg[1:] or ['default', 'args'])

--Scott David Daniels
scott.dani...@acm.org
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Re: Why do operators and methods of built-in types differ

[Scott David Daniels]

Csaba Hoch wrote:

if I write the following:
   >>> 1+1
   2
it seems to be exactly equivalent to this:
   >>> (1).__add__(1)
   2 
However, if I write invalid code and try to add a list to an int, the

errors will be different: 

As has been explained, binary operators are trickier than the above
seems to show.  Here is how to get the full behavior:
>>> import operator
>>> operator.add(1,[])
Traceback (most recent call last):
  File "", line 1, in 
operator.add(1,[])
TypeError: unsupported operand type(s) for +: 'int' and 'list'


--Scott David Daniels
scott.dani...@acm.org
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Re: is python Object oriented??

[thmpsn . m . k]

On Jan 30, 2:32 pm, Michael Torrie  wrote:
> Veerendra Ganiger wrote:
> > Python is not purely object oriented programming, because we can write
> > functions without any class.
> > You are right, predefined class attributes are available when we write or
> > execute a piece of python code without defining class, that means it's just
> > using objects for it's purpose. It does not mean its purely object oriented.
>
> To be clear, python does not force you to lay out your code according to
> some strict object-oriented paradigm.  But Python itself is still purely
> object-oriented, as is your script when parsed.
>
> This function without a class that you mentioned, is in fact an object
> with attributes.  You can pass a function around just like any other
> object.  Even calling a function is invoked like so:
>
> myfunc.__call__(params)
>
> So necessitating that code be inside a class has nothing to do with
> object-oriented programming.  Let's not forget that classes are
> themselves objects (metaobjects in smalltalk parlance if I recall
> correctly).
>
> Now python does not have any way besides lambda expressions of creating
> unbound function objects, but in practice this doesn't matter as I can
> rebind names freely.  I can still do:
>
> a=myfunc
> myfunc=some other expression or object
>
> > It all depends on implementation, I think even we can make "C" object
> > oriented with proper implementation.
>
> Indeed, any code based on gobject libraries can be object-oriented in
> design and function.

But it's only a faking, and things such as inheritance and
polymorphism are implemented clumsily (actually I'm not even sure
about polymorphism). And of course, there are still no private
members.

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Re: nth root

[Dan Goodman]

Mark Dickinson wrote:

Well, random numbers is one thing.  But how about the following:


n = 12345**13
n

154662214940914131102165197707101295849230845947265625L

int(n ** (1./13))  # should be 12345; okay

12345

int((n-1) ** (1./13))  # should be 12344; oops!

12345


Good point! Oops indeed. :-)

Dan

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Re: Python Doc 2.6 vs 2.5--A Matter of Format?

[Stephen Hansen]

On Sat, Jan 31, 2009 at 9:14 AM, W. eWatson  wrote:I see  for 2.5 and  for 2.6. I'm guessing these two pages differ somewhat in formats simply because someone decided to do so, and not that I'm in the wrong place for each of the two versions, correct? For example, somewhere down in the 2.5, I should find the 2.6 equivalent of ?The entire documentation system for Python was changed in 2.6/3.0; it now uses ReST instead of LaTeX as its source and has a different toolchain(Sphinx) to build the HTML docs from the source material, do all the linking/indexing, and all of that jazz. Its mostly but not entirely the same: there's some structural changes that go beyond format, but all the content is there, I believe. I believe the "genindex" for 2.5 that you're looking for is at http://www.python.org/doc/2.5/lib/genindex.html ... you get it by hitting 'I' on the upper right hand corner of the page after you go into an actual documentaiton catalog. (E.g., "Library Reference" as opposed to that main index page)--S



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Re: persistent TCP connection in python using socketserver

[markobrien85]

On Jan 30, 5:54 am, Jean-Paul Calderone  wrote:
> On Thu, 29 Jan 2009 08:38:43 -0800 (PST), markobrie...@gmail.com wrote:
> >G'day
>
> >I'm currentlyusingsocketserverto build a simple XMLSocket (an XML
> >based protocol used for communication between flash and the outside
> >world) server. I've got flash establishing aconnection, sending a
> >request and mypythonserver responding. However at this point
> >socketserverterminates theconnection. Which is bad, since i need a
> >persistentconnectionso i can push data from the server to the client
> >without the overhead of polling.
>
> If you don't want theconnectionto close, then don't let the request
> complete.  SocketServerimplements logic for single request/response
> perconnection.  You can change this by making your requests take a
> really long time (until you're done with theconnection) or you can
> override the behavior which closes theconnectionafter a response.
>
> Or you could use the socket module, on which theSocketServermodule is
> based.  Or you could use Twisted, another higher-level package built on
> the socket module (mostly).  Actually, I recommend Twisted, since it will
> mostly isolate you from boring low-level details and let you implement
> whatever high-level behavior you're after (I know that a bunch of people
> have used it to communicate with Flash, for example).
>
> Jean-Paul

Cheers mate I had a look into twisted but was put off by the FAQ
stating 1.0+ modules may or may not be stable, and only the 'core' is.
I don't wanna be messing around with a potentially buggy server, so im
gonna roll my own using the sockets module.


Thanks for your help !
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Re: nth root

[Mark Dickinson]

On Jan 31, 4:48 pm, Dan Goodman  wrote:
> I don't think accuracy is too big a problem here actually (at least for
> 13th roots). I just tested it with several hundred thousand random 100
> digit numbers and it never made a mistake.

Well, random numbers is one thing.  But how about the following:

>>> n = 12345**13
>>> n
154662214940914131102165197707101295849230845947265625L
>>> int(n ** (1./13))  # should be 12345; okay
12345
>>> int((n-1) ** (1./13))  # should be 12344; oops!
12345

Mark

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Re: is python Object oriented??

[Stephen Hansen]

On Sat, Jan 31, 2009 at 9:08 AM,   wrote:On Jan 30, 12:15 am, Chris Rebert  wrote:
> - Python supports encapsulation. Prefixing an attribute/method with an
> underscore indicates that other programmers should treat it as
> 'private'. However, unlike B&D languages, Python itself does nothing
> to enforce this privacy, leaving it instead to the good judgement of
> the programmer, under the philosophy that "We're all consenting adults
> here".

How do you know? (I know I'm not.)

Seriously, though, the lack of private members does allow for ugly
hacks in user code, and you know there are always ugly hackers.
So what, though?If you're a application developer, writing your own code: just don't do it.You've now achieved enforced encapsulation! Why does the languageneed to check that?If you're the user of a library and you need access to a private memberof that library: again, just don't do it! Write a patch and maintain aprivate fork to expose the member function, and submit it to the developerand hope it gets included so you don't have to maintain the private fork.For those people who need access to that internal Right Now and don'twant to wait for the developer to expose it, because its important to themwhy should the language forbid it? Sure, its an ugly hack. But so what? They're doing it, at the risk of future breakage if anything changes inthat undocumented internal detail, because they need to. There aresituations where maintaining a private fork to expose something in alibrary is a far greater burden and not worth it.If you're the writer of a library, why do you even care if the people whouse it access an undocumented internal? If anything breaks its notyour problem.If you're in some corporate environment which has a 'no fiddling withthe privates of another teams modules' -- why do you need the languageto enforce that restriction? If your employees aren't following the codingstandards of your own organization, that's a problem. Surely it'd come upvery quickly with even the most cursory of reviews, after all "obj._variable"is really obviously not "self._variable" and so pretty obviously accessingsomeone elses private state.If you're in an open source environment and are worried about qualityof code from lots of contributors who aren't being paid: again, reviewsshould be happening /anyways/.In the end, why bother? If you believe in absolute encapsulation itsextremely easy for you to get it in Python, today... don't touch someoneelses privates.  
> This allows people to meddle with internals, at their own risk,
> if it ends up being absolutely necessary.

If it ends up being necessary, the class's design is flawed. (Though
in this case, the flaw is easily solved by simply providing a getter.)Sure, the design is flawed. Doesn't change the fact that you need to accessthat internal state. "Providing a getter" is not necessarily simple: what ifits someone elses code? At the very least you have to maintain a privatefork then /or/ wait until they get around to fixing the design. Sometimes that's no big deal. Sometimes it is. 
In the absence of private/protected, Python should at least provide
something similar to C++'s 'const' or Java's 'final'. (Similar, not
equivalent, because then the object itself wouldn't be able to
manipulate its own members!)I find marking my constants as SOME_CONSTANT instead of some_constantto be more then sufficient usually. In the case where I do want to let someoneread a piece of data and not write it, I find a getter accessing a private membervariable without a corresponding setter perfectly fine.If the users of the code choose to dig inside my class and fiddle with thatprivate member -- woe on them! I wash my hands of any trouble theyhave.--Stephen 



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Re: nth root

[Mensanator]

On Jan 31, 10:53 am, Mensanator  wrote:
> On Jan 31, 8:05 am, Mark Dickinson  wrote:
>
> > On Jan 31, 1:23 pm, Steve Holden  wrote:
>
> > > Much more significant points, given the limited precision of the doubles
> > > Python will be using. Could gmpy do this better, I wonder?
>
> > Almost certainly, if exact results are wanted!  At least, GMP has
> > an mpz_root function; I don't know offhand whether gmpy makes it
> > accessible from Python.
>
> > Mark
>
> What am I doing wrong here?
>
> IDLE 2.6b1
>
> >>> import timeit
> >>> from gmpy import root
> >>> root(4021503534212915433093809093996098953996019232,13)
> (mpz(3221), 0)
> >>> t1 = timeit.Timer("x = root(a,r)", "a = 
> >>> 4021503534212915433093809093996098953996019232; r = 13")
> >>> t1.timeit()
>
> Traceback (most recent call last):
>   File "", line 1, in 
>     t1.timeit()
>   File "C:\Python26\lib\timeit.py", line 193, in timeit
>     timing = self.inner(it, self.timer)
>   File "", line 6, in inner
> NameError: global name 'root' is not defined

Never mind, I figured it out.

>>> import gmpy
>>> a=gmpy.mpz(4021503534212915433093809093996098953996019232)
>>> r=13
>>> t1 = timeit.Timer("x = root(a,r)", "from gmpy import root; from __main__ 
>>> import a,r")
>>> t1.timeit()
4.7018698921850728

For comparison:

>>> t2 = timeit.Timer("x = n**power", "n = 
>>> 4021503534212915433093809093996098953996019232.; power = 1./13")
>>> t2.timeit()
0.43993394115364026
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Python Doc 2.6 vs 2.5--A Matter of Format?

[W. eWatson]

I see  for 2.5 and  
for 2.6. I'm guessing these two pages differ somewhat in formats simply 
because someone decided to do so, and not that I'm in the wrong place for 
each of the two versions, correct? For example, somewhere down in the 2.5, I 
should find the 2.6 equivalent of ?

--
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 (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)
  Obz Site:  39° 15' 7" N, 121° 2' 32" W, 2700 feet

Web Page: 

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Re: is python Object oriented??

[thmpsn . m . k]

On Jan 30, 12:15 am, Chris Rebert  wrote:
> - Python supports encapsulation. Prefixing an attribute/method with an
> underscore indicates that other programmers should treat it as
> 'private'. However, unlike B&D languages, Python itself does nothing
> to enforce this privacy, leaving it instead to the good judgement of
> the programmer, under the philosophy that "We're all consenting adults
> here".

How do you know? (I know I'm not.)

Seriously, though, the lack of private members does allow for ugly
hacks in user code, and you know there are always ugly hackers.

> This allows people to meddle with internals, at their own risk,
> if it ends up being absolutely necessary.

If it ends up being necessary, the class's design is flawed. (Though
in this case, the flaw is easily solved by simply providing a getter.)

> The enforcement point is
> largely academic anyway, as most languages' reflection APIs let you
> poke at ostensibly "private" things.

If you're talking about getters, then note that this doesn't let you
modify the member (unless there's a corresponding setter).

In the absence of private/protected, Python should at least provide
something similar to C++'s 'const' or Java's 'final'. (Similar, not
equivalent, because then the object itself wouldn't be able to
manipulate its own members!)

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Re: Where to host a (Python) project?

[ajaksu]

On Jan 31, 1:03 pm, andrew cooke  wrote:
> On Jan 31, 11:22 am, eliben  wrote:
>
> > code.google.com provides all of these in a free and convenient manner.
> > Recommended.
>
> unfortunately google don't seem that reliable ;o)  (have you tried a
> google search today?)

You can mirror at LP, bitbucket, github, etc.
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Re: Empty string is False right?

[Stephen Hansen]

On Sat, Jan 31, 2009 at 4:36 AM, AJ Ostergaard  wrote:I'm not suggesting it's not operating as advertised - I'm suggesting the 'advertising' is slightly sguiffy if you catch my drift. I guess it's just me that finds it slightly counter intuitive. Surely intuitively the _expression_ is "and" and therefore should always return a boolean?Boolean operators just aren't guaranteed to return a boolean /type/ -- but instead a boolean /_expression_/, that if evaluated is true or false. The difference is important -- and although it might be partly for historical reasons (after all, there was no boolean /type/ until Python 2.3. That's not really all that long ago), it also has quite a few useful properties that aren't necessecarily immediately obvious but are used in a variety of places.A common one is the and/or "ternary" _expression_ that pre-dates the addition of conditional expressions to Python 2.5:>>> test = True>>> test and "Apples" or "Oranges"'Apples'>>> test = False>>> test and "Apples" or "Oranges"'Oranges'In Python 2.5., that can be rewritten to:>>> test = True>>> "Apples" if test else "Oranges"'Apples'>>> test = False>>> "Apples" if test else "Oranges"'Oranges'Its part of why you aren't supposed to compare boolean results/tests/expressions against True or False directly usually (besides /just/ style). You do:if _expression_:   print "Was true!"Not:if _expression_ is True:    print "Was true!"--Stephen



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Re: nth root

[Mensanator]

On Jan 31, 8:05 am, Mark Dickinson  wrote:
> On Jan 31, 1:23 pm, Steve Holden  wrote:
>
> > Much more significant points, given the limited precision of the doubles
> > Python will be using. Could gmpy do this better, I wonder?
>
> Almost certainly, if exact results are wanted!  At least, GMP has
> an mpz_root function; I don't know offhand whether gmpy makes it
> accessible from Python.
>
> Mark

What am I doing wrong here?

IDLE 2.6b1
>>> import timeit
>>> from gmpy import root
>>> root(4021503534212915433093809093996098953996019232,13)
(mpz(3221), 0)
>>> t1 = timeit.Timer("x = root(a,r)", "a = 
>>> 4021503534212915433093809093996098953996019232; r = 13")
>>> t1.timeit()

Traceback (most recent call last):
  File "", line 1, in 
t1.timeit()
  File "C:\Python26\lib\timeit.py", line 193, in timeit
timing = self.inner(it, self.timer)
  File "", line 6, in inner
NameError: global name 'root' is not defined
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Re: nth root

[Dan Goodman]

Mark Dickinson wrote:

I'd also be a bit worried about accuracy.   Is it important to you
that the
integer part of the result is *exactly* right, or is it okay if
(n**13)**(1./13) sometimes comes out as slightly less than n, or if
(n**13-1)**(1./13) sometimes comes out as n?


I don't think accuracy is too big a problem here actually (at least for 
13th roots). I just tested it with several hundred thousand random 100 
digit numbers and it never made a mistake. The precision of double ought 
to easily guarantee a correct result. If you let x=int(1e100**(1./13)) 
then ((x+1)**13-x**13)/x**13=2.6e-7 so you only need around the first 8 
or 9 digits of the 100 digit number to compute the 13th root exactly 
(well within the accuracy of a double).


OTOH, suppose you were doing cube roots instead then you would need the 
first 35 digits of the 100 digit number and this is more accurate than a 
double. So for example int(1e100**(1./3)) is a long way from being the 
integer part of the true cube root (it's between 10**18 and 10**19 away).


Dan

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fastest way to detect a user type

[Robin Becker]

Whilst considering a port of old code to python 3 I see that in several 
places we are using type comparisons to control processing of user 
instances (as opposed to instances of built in types eg float, int, str)


I find that the obvious alternatives are not as fast as the current 
code; func0 below. On my machine isinstance seems slower than type for 
some reason. My 2.6 timings are


C:\Tmp>\Python\lib\timeit.py -s"import t;v=t.X()" t.func0(v)
100 loops, best of 3: 0.348 usec per loop

C:\Tmp>\Python\lib\timeit.py -s"import t;v=t.X()" t.func1(v)
100 loops, best of 3: 0.747 usec per loop

C:\Tmp>\Python\lib\timeit.py -s"import t;v=t.X()" t.func2(v)
100 loops, best of 3: 0.378 usec per loop

C:\Tmp>\Python\lib\timeit.py -s"import t;v=t.X()" t.func3(v)
100 loops, best of 3: 0.33 usec per loop

C:\Tmp>\Python\lib\timeit.py -s"import t;v=t.X()" t.func0(1)
100 loops, best of 3: 0.477 usec per loop

C:\Tmp>\Python\lib\timeit.py -s"import t;v=t.X()" t.func1(1)
100 loops, best of 3: 1.14 usec per loop

C:\Tmp>\Python\lib\timeit.py -s"import t;v=t.X()" t.func2(1)
100 loops, best of 3: 1.16 usec per loop

C:\Tmp>\Python\lib\timeit.py -s"import t;v=t.X()" t.func3(1)
100 loops, best of 3: 1.14 usec per loop

so func 3 seems to be the fastest option for the case when the first 
test matches, but is poor when it doesn't. Can anyone suggest a better 
way to determine if an object is a user instance?


##
from types import InstanceType
class X:
__X__=True

class V(X):
pass

def func0(ob):
t=type(ob)
if t is InstanceType:
pass
elif t in (float, int):
pass
else:
pass

def func1(ob):
if isinstance(ob,X):
pass
elif type(ob) in (float, int):
pass
else:
pass

def func2(ob):
if getattr(ob,'__X__',False):
pass
elif type(ob) in (float, int):
pass
else:
pass

def func3(ob):
if hasattr(ob,'__X__'):
pass
elif type(ob) in (float, int):
pass
else:
pass
##

--
Robin Becker
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Re: Empty string is False right?

[Diez B. Roggisch]

AJ Ostergaard schrieb:

Hi Ralf,

Thanks for that but why:

 >>> '' and True
''

Surely that should be False?!?


No. Please read the section in the language reference about the and/or 
operators.


"and" will return the first false value, or the right side. Thus

'' and True -> ''

True and '' -> ''

'a' and True -> True

True and 'a' -> 'a'

"or" does the same, obviously with the or-semantics:


'' or False -> False
False or '' -> ''
'' or True -> True
True or '' -> True
'a' or False -> 'a'
False or 'a' -> 'a'

Diez

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Re: glob.fnmatch (was "search speed")

[rdmurray]

Quoth Tim Chase :
> rdmur...@bitdance.com wrote:
> > What you want is:
> > 
> > from fnmatch import fnmatch
> 
> Oh, that's head-smackingly obvious now...thanks!
> 
> My thought process usually goes something like
> 
> """
> I want to do some file-name globbing
> 
> there's a glob module that looks like a good place to start
> 
> hmm, dir(glob) tells me there's a fnmatch thing that looks like 
> what I want according to help(glob.fnmatch)
> 
> oh, the fnmatch() function is inside this glob.fnmatch thing
> 
> so, I want glob.fnmatch.fnmatch()
> """
> 
> It never occurred to me that fnmatch was its own importable 
> module.  

I did a help(glob), saw that fnmatch wasn't in there, did a dir(glob),
saw fnmatch and was puzzled, so I looked up the glob doc page on
docs.python.org for glob.  There was a cross reference at the bottom
of the page to fnmatch, and it was only at that point that I went:
"oh, duh" :)

--RDM

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Re: Tkinter w.pack()?

[W. eWatson]

Gabriel Genellina wrote:
En Thu, 29 Jan 2009 14:55:13 -0200, W. eWatson  
escribió:

Gabriel Genellina wrote:
En Thu, 29 Jan 2009 02:57:04 -0200, W. eWatson 
 escribió:



The word pack doesn't exist on the NMT pdf. Maybe there's a newer one?

 There is a PDF version of "An Introduction to Tkinter" here:
http://www.pythonware.com/library/

Thanks. I have it but it's an odd one to search on "pack(". There may 
be over 100 reference to pack(. It's probably explained there 
somewhere, but how many times do I want to press the search key? I 
have it printed out too. I guess I need to eyeball it. It's probably 
faster. Maybe find the section (geometry?) where it and others like it 
are found. There is an index, but it's a pitiful one page.


Uh? The very first occurence of "pack" is in the Table of Contents, "The 
pack geometry manager". (You may want to improve your search skills :) )


Yes, that's correct, but I was looking for "pack(". It all depends on one's 
perspective on how to search. I'll not labor the point.


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Re: Tkinter w.pack()?

[W. eWatson]

Steve Holden wrote:

W. eWatson wrote:

r wrote:

On Jan 28, 10:12 pm, "W. eWatson"  wrote:

Where in the world is a description of pack() for Tkinter widgets? Is it
some sort of general method for all widgets? I'm looking in a few
docs that
use it without ever saying where it is described. For one,
. In the NM Tech pdf on
Tkinter,
it's not found anywhere. I see Universal methods for widgets, but no
mention
of pack(). package, packed, but no pack.

did you try here :)
http://effbot.org/tkinterbook/pack.htm

Thanks. I have the site bookmarked, but it's hard to search. I posted a
comment to them that they should have it in pdf form.


http://letmegooglethatforyou.com/?q=site%3Aeffbot.org%2Ftkinterbook+pack

regards
 Steve
Well, that's an interesting "link". Another side of Google facilities? Maybe 
you're using Snagit or its brethern? However, I'm interested in searching a 
pdf, which, of course, doesn't yet exist.


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Re: Why GIL? (was Re: what's the point of rpython?)

[Aahz]

In article <7xr62ufv1c@ruckus.brouhaha.com>,
Paul Rubin   wrote:
>a...@pythoncraft.com (Aahz) writes:
>>
>> CPython's "primitive" storage management has a lot to do with the
>> simplicity of interfacing CPython with external libraries.  Any solution
>> that proposes to get rid of the GIL needs to address that.
>
>This, I don't understand.  Other languages like Lisp and Java and
>Haskell have foreign function interfaces that easier to program than
>Python's, -and- they don't use reference counts.  There's usually some
>primitive to protect objects from garbage collection while the foreign
>function is using them, etc.  The Java Native Interface (JNI) and the
>Haskell FFI are pretty well documented.  The Emacs Lisp system is not
>too hard to figure out from examining the source code, etc.

This is the first time I've heard about Java being easier to interface
than Python.  I don't work at that level myself, so I rely on the
informed opinions of other people; can you provide a summary of what
makes those FFIs easier than Python?
-- 
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programs, then the first woodpecker that came along would destroy civilization.
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Re: Why do operators and methods of built-in types differ

[Gabriel Genellina]

En Sat, 31 Jan 2009 11:03:13 -0200, andrew cooke   
escribió:





Just a correction: according to the doc, NotImplemented is not an
error, but a returned value.


curious, so it is.  i wonder why there is both a special return value
(NotIMplemented) and a related exception (NotImplementedError).  seems
very odd to have a value...


I consider it an optimization. Raising an exception is more costly than  
returning a value, and this failure is likely to happen often (not all  
types define all possible operators). AFAIK this is only recognized by the  
binary operators (__add__, __iadd__, etc) and rich comparisons (__eq__,  
__lt__, etc.)


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Re: py2exe + SQLite problem

[Gabriel Genellina]

En Sat, 31 Jan 2009 11:51:16 -0200, Armin  escribió:

Gabriel Genellina wrote:

En Fri, 30 Jan 2009 09:50:08 -0200, Armin  escribió:


 Right at the end: "To install data files directly in the target  
directory, an empty string should be given as the directory."

 setup(...,
  data_files=[
   ('', ['list/of/file/names',  
'perhaps/including/source/directory']),

   ]
 )


Yes ... so far the theory :)

As posted before ... set's my script (python 2.3):


You didn't tell us that you were using version 2.3 -- it's important, as  
the current stable releases are 2.6 and 3.0. Anyway, this should work in  
2.3 too.



from distutils.core import setup
import py2exe

setup(windows=['dpconf.py'],
 data_files=[ "", ["proj_db","gsd_db","dachs2.xbm"]]
 )



Comparing my example and yours, you lack a parenthesis level:

setup(windows=['dpconf.py'],
  data_files=[("", ["proj_db","gsd_db","dachs2.xbm"])]
  )


When I create the distribution I got the following err msg:

*** copy data files ***
warning: install_data: setup script did not provide a directory for ''  
-- installing right in 'C:\pyDPCONF.2.3-dev\dist'

error: can't copy '': doesn't exist or not a regular file

Looks a little bit inconsistent ?


O thou of little faith, try again...

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Re: py2exe + SQLite problem

[Thomas Heller]

Armin schrieb:
> As posted before ... set's my script (python 2.3):
> 
> from distutils.core import setup
> import py2exe
> 
> setup(windows=['dpconf.py'],
>  data_files=[ "", ["proj_db","gsd_db","dachs2.xbm"]]
>  )
> 
> When I create the distribution I got the following err msg:
> 
> *** copy data files ***
> warning: install_data: setup script did not provide a directory for '' 
> -- installing right in 'C:\pyDPCONF.2.3-dev\dist'
> error: can't copy '': doesn't exist or not a regular file

>From the Python docs (chapter 'writing the setup script):

"""
data_files specifies a sequence of (directory, files) pairs in the following 
way:

setup(...,
  data_files=[('bitmaps', ['bm/b1.gif', 'bm/b2.gif']),
  ('config', ['cfg/data.cfg']),
  ('/etc/init.d', ['init-script'])]
 )
"""

So, it looks like you should use

> setup(windows=['dpconf.py'],
>  data_files=[("", ["proj_db","gsd_db","dachs2.xbm"])]
   ^ ^
>  )

Thomas
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Re: Why do operators and methods of built-in types differ

[Christian Heimes]

andrew cooke schrieb:
>> Just a correction: according to the doc, NotImplemented is not an
>> error, but a returned value.
> 
> curious, so it is.  i wonder why there is both a special return value
> (NotIMplemented) and a related exception (NotImplementedError).  seems
> very odd to have a value...

They are different and unrelated things. The NotImplentedError is an
exception class while NotImplemented is a singleton like None. When a
method like __add__ can't handle the other object it returns
NotImplemented. It doesn't raise a NotImplementedError. The
NotImplemented singleton is an optimization. The interpreter just has to
compare the memory address of the returned value with the address of
NotImplemented. That's a super fast op in C.

Christian

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Re: Where to host a (Python) project?

[andrew cooke]

On Jan 31, 11:22 am, eliben  wrote:
> code.google.com provides all of these in a free and convenient manner.
> Recommended.

unfortunately google don't seem that reliable ;o)  (have you tried a
google search today?)
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Re: Where to host a (Python) project?

[eliben]

andrew cooke wrote:
> Hi,
>
> I have a new project, that I just released in beta (http://
> www.acooke.org/lepl - a recursive decent parser with full
> backtracking).  At the moment I am using pypi and setuptools for
> distribution (it's a pure python package) and I am happy with hosting
> static web pages (the manual and api doc linked to above) on my own
> site (I did try the packages.python.org web pages, but it seemed
> pointless duplicating my own).
>
> However, i am thinking I could really do with:
> - a mailing list
> - simple bug tracking
> - subversion

code.google.com provides all of these in a free and convenient manner.
Recommended.
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Re: Empty string is False right?

[Grant Edwards]

On 2009-01-31, Vlastimil Brom  wrote:
> 2009/1/31 AJ Ostergaard :
>> Hi Ralf,
>>
>> Thanks for that but why:
>>
> '' and True
>> ''
>>
>> Surely that should be False?!?
>>
>> Regards,
>> AJ
>>
>>
> see the docs:
> http://docs.python.org/reference/expressions.html#boolean-operations
>
> "The expression x and y first evaluates x; if x is false,

But that doesn't mean "x is False" in the strict Python
expression sense of the phrase.  It means if bool(x) is False
(or something reasonably close to that).

> its value is returned; otherwise, y is evaluated and the
> resulting value is returned."

-- 
Grant

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Re: Where to host a (Python) project?

[Michele Simionato]

On Jan 31, 12:46 pm, andrew cooke  wrote:
> Any recommendations?

Google Code seems fine.
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Re: nth root

[Mark Dickinson]

On Jan 31, 1:23 pm, Steve Holden  wrote:
> Much more significant points, given the limited precision of the doubles
> Python will be using. Could gmpy do this better, I wonder?

Almost certainly, if exact results are wanted!  At least, GMP has
an mpz_root function; I don't know offhand whether gmpy makes it
accessible from Python.

Mark
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Re: nth root

[Mark Dickinson]

On Jan 31, 1:23 pm, Steve Holden  wrote:
> [Mark]
> > power operation.  The integer -> float conversion is probably quite
> > significant, timewise.
>
> I bow to your superior intuition!

Here's another timing that shows the significance of the int -> float
conversion: (non-debug build of the trunk)

>>> t1 = timeit.Timer("x = n**power", "n = 
>>> 4021503534212915433093809093996098953996019232; power = 1./13")
>>> t2 = timeit.Timer("x = n**power", "n = 
>>> 4021503534212915433093809093996098953996019232.; power = 1./13")
>>> t1.timeit()
0.34778499603271484
>>> t2.timeit()
0.26025009155273438

I've got a patch posted to the tracker somewhere that improves
the accuracy of long->float conversions, while also speeding them
up a tiny bit (but not a lot...).

Mark
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Re: py2exe + SQLite problem

[Armin]

Gabriel Genellina wrote:

En Fri, 30 Jan 2009 09:50:08 -0200, Armin  escribió:




Right at the end: "To install data files directly in the target 
directory, an empty string should be given as the directory."


setup(...,
  data_files=[
   ('', ['list/of/file/names', 
'perhaps/including/source/directory']),

   ]
 )


Yes ... so far the theory :)

As posted before ... set's my script (python 2.3):

from distutils.core import setup
import py2exe

setup(windows=['dpconf.py'],
data_files=[ "", ["proj_db","gsd_db","dachs2.xbm"]]
)

When I create the distribution I got the following err msg:

*** copy data files ***
warning: install_data: setup script did not provide a directory for '' 
-- installing right in 'C:\pyDPCONF.2.3-dev\dist'

error: can't copy '': doesn't exist or not a regular file

Looks a little bit inconsistent ?

--Armin
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Re: Where to host a (Python) project?

[Martin]

2009/1/31 andrew cooke :
> On Jan 31, 9:59 am, Martin  wrote:
>> There's tigris.org, savannah (savannah.gnu.org, nongnu.org),
>> launchpad. All of them are fine to some extent, you might want to read
>> up on PyMotW about how Doug Hellmann decided where to host his stuff.
>
> all i can find is that he is writing his own!
> http://blog.doughellmann.com/search/label/codehosting
> (his reqs are quite different to mine - I am looking for an external
> provider because I do not want to host dynamic pages myself).

Darn, my bad. I just remembered that something happened in terms of
hosting on his site, I thought he had decided on this:

http://blog.doughellmann.com/2008/12/moving-pymotw-to-public-repository.html
(seems he didn't have any time...)

anyway, tigris, nongnu and savannah are hopefully at least useable
information :)

/Martin



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Re: glob.fnmatch (was "search speed")

[Tim Chase]

rdmur...@bitdance.com wrote:

Quoth Tim Chase :
PS:  as an aside, how do I import just the fnmatch function?  I 
tried both of the following and neither worked:


   from glob.fnmatch import fnmatch
   from glob import fnmatch.fnmatch

I finally resorted to the contortion coded below in favor of
   import glob
   fnmatch = glob.fnmatch.fnmatch


What you want is:

from fnmatch import fnmatch


Oh, that's head-smackingly obvious now...thanks!

My thought process usually goes something like

"""
I want to do some file-name globbing

there's a glob module that looks like a good place to start

hmm, dir(glob) tells me there's a fnmatch thing that looks like 
what I want according to help(glob.fnmatch)


oh, the fnmatch() function is inside this glob.fnmatch thing

so, I want glob.fnmatch.fnmatch()
"""

It never occurred to me that fnmatch was its own importable 
module.  


-tkc



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Re: Empty string is False right?

[Steve Holden]

AJ Ostergaard wrote:
> I'm not suggesting it's not operating as advertised - I'm suggesting the
> 'advertising' is slightly sguiffy if you catch my drift. I guess it's
> just me that finds it slightly counter intuitive. Surely intuitively the
> expression is "and" and therefore should always return a boolean?
> 
> I'll shut up now. ;)
> 
You might think so, and it wouldn't be an entirely unreasonable thought,
but in practice it makes a lot of sense to retain the original value
where possible.

The fact is that any left-hand operand that evaluates to false in a
Boolean context can be used as it stands rather than being converted to
Boolean first. So the conversion is essentially useless processing.

regards
 Steve
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Re: Empty string is False right?

[D'Arcy J.M. Cain]

On Sat, 31 Jan 2009 12:16:19 +
AJ Ostergaard  wrote:
>  >>> '' and True
> ''
> 
> Surely that should be False?!?

Why?  The first value evaluates to False in a boolean context and
thus is returned in the above statement due to short circuit
evaluation but is not itself False.  You wouldn't expect the following
statement to be True.

>>> '' is False
False

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Re: nth root

[Steve Holden]

Mark Dickinson wrote:
> On Jan 31, 5:43 am, "Tim Roberts"  wrote:
>> Dan,
>>
>> Thanks - you're probably right - just my intuition said to me that rather 
>> than calculating that the 13th root of 
>> 4021503534212915433093809093996098953996019232
>> is 3221.2904208350265
>> there must be a quicker way of finding out its between 3221 and 3222
>>
>> but perhaps not.
> 
> I don't think you'll find anything much quicker than n**(1./13)
> (though I hope
> that if you're doing this millions of time then you're precomputing
> the 1./13
> rather than redoing the division every single time.
> 
Compared with the computation involved in the power computation I think
you'll find this makes a negligible difference in timing. But that's
just mu gut instinct, and we both know that a benchmark is the only way
to be certain, right? It just seems like a possibly premature
optimization to me. [sigh. I had to start this, didn't i?]

>>> t1 = timeit.Timer("x =
4021503534212915433093809093996098953996019232**(1.0/13)")
>>> t2 = timeit.Timer("x =
4021503534212915433093809093996098953996019232**power", "power=1.0/13")
>>> t1.timeit()
1.486610351562
>>> t2.timeit()
1.378485015869
>>>

Hmm, well, I suppose an 9% speed gain might be worth it.


> What happens behind the scenes here is that your integer is
> immediately
> converted to a float, then the system math library is used for the
> power operation.  The integer -> float conversion is probably quite
> significant, timewise.
> 
I bow to your superior intuition!

> I'd also be a bit worried about accuracy.   Is it important to you
> that the
> integer part of the result is *exactly* right, or is it okay if
> (n**13)**(1./13) sometimes comes out as slightly less than n, or if
> (n**13-1)**(1./13) sometimes comes out as n?
> 
Much more significant points, given the limited precision of the doubles
Python will be using. Could gmpy do this better, I wonder?

regards
 Steve
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Re: Where to host a (Python) project?

[andrew cooke]

On Jan 31, 9:59 am, Martin  wrote:
> There's tigris.org, savannah (savannah.gnu.org, nongnu.org),
> launchpad. All of them are fine to some extent, you might want to read
> up on PyMotW about how Doug Hellmann decided where to host his stuff.

all i can find is that he is writing his own!
http://blog.doughellmann.com/search/label/codehosting
(his reqs are quite different to mine - I am looking for an external
provider because I do not want to host dynamic pages myself).

anyway, if that was what you mean, fine - i just wonder if i am
missing something?

thanks,
andrew
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Re: is python Object oriented??

[Steve Holden]

MC wrote:
> Re
> 
>> ‘builtin’ is not a class.
> 
> I think "object" ; not only "class"
> And "builtin" is an object.
> 
You can think what you like, but there is a fundamental difference
between methods of a class and functions of a module. Until you
appreciate that you will likely make mistakes. Don't worry, though, we
all learn from our mistakes.

regards
 Steve
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Steve Holden+1 571 484 6266   +1 800 494 3119
Holden Web LLC  http://www.holdenweb.com/

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