date:20081125

Hi,

In the name of self-education can anyone share some pointers, links,
modules, etc that I might use to begin learning how to do some
metaprogramming. That is, using code to write code (right?)

Cheers,

- Rafe
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Re: Getting in to metaprogramming

2008-11-25 Thread Michele Simionato

On Nov 25, 11:08 am, Rafe [EMAIL PROTECTED] wrote:
 Hi,

 In the name of self-education can anyone share some pointers, links,
 modules, etc that I might use to begin learning how to do some
 metaprogramming. That is, using code to write code (right?)

 Cheers,

 - Rafe

The word metaprogramming has many meanings. It covers code
generation, as you say,
but also a lots of other techniques; for instance you do
metaprogramming with decorators
when write functions operating over functions, or with metaclasses
when you write classes
operating over classes. You should clarify what you are interested in.
For instance, are
you interested in metaprogramming in Python only or you want a more
general introduction?
Have you read the Wikipedia entry?
http://en.wikipedia.org/wiki/Metaprogramming
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Re: Instance attributes vs method arguments

snip
 It is always good practice to provide default values for
 instance variables in the class definition, both to enhance
 readability and to allow adding documentation regarding
 the variables, e.g.

 class Class_a:

    # Foo bar
    a = None

    # Foo baz
    b = None
snip

Those are not instance 'variables' (attributes), they are class
attributes. I used to do that in JScript, so I did it in python when I
moved over. It caused a lot of trouble for me as a beginner. I was
eventually given the advice to stop it. I haven't looked back since
(until now). I think you would just be adding a new self.a which
blocks access to your class.a, but I'm still shaky on this knowledge.

Instance attribute defaults would be inside __init__() and before
unpacking the *args.

- Rafe

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Re: Instance attributes vs method arguments

2008-11-25 Thread John O'Hagan

On Tue, 25 Nov 2008, Marc 'BlackJack' Rintsch wrote:
 On Tue, 25 Nov 2008 07:27:41 +, John O'Hagan wrote:
  Is it better to do this:
 
  class Class_a():
  def __init__(self, args):
  self.a = args.a
  self.b = args.b
  self.c = args.c
  self.d = args.d
  def method_ab(self):
  return self.a + self.b
  def method_cd(self):
  return self.c + self.d
 
  or this:
 
  class Class_b():
  def method_ab(self, args):
  a = args.a
  b = args.b
  return a + b
  def method_cd(self, args)
  c = args.c
  d = args.d
  return c + d
 
  ?
 
  Assuming we don't need access to the args from outside the class, is
  there anything to be gained (or lost) by not initialising attributes
  that won't be used unless particular methods are called?

 The question is if `args.a`, `args.b`, …, are semantically part of the
 state of the objects or not.  Hard to tell in general.

Would you mind elaborating a little on that first sentence?

 I know it's a made up example but in the second class I'd ask myself if
 those methods are really methods, because they don't use `self` so they
 could be as well be functions or at least `staticmethod`\s.

I guess I went overboard keeping the example simple :) : the real case has 
many methods, and they all use self (except one, actually, so I'm looking 
up static methods now; thanks). 


Regards,

John


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Re: Instance attributes vs method arguments

2008-11-25 Thread Marc 'BlackJack' Rintsch

On Tue, 25 Nov 2008 10:48:01 +, John O'Hagan wrote:

 On Tue, 25 Nov 2008, Marc 'BlackJack' Rintsch wrote:
 On Tue, 25 Nov 2008 07:27:41 +, John O'Hagan wrote:
  Is it better to do this:
 
  class Class_a():
 def __init__(self, args):
 self.a = args.a
 self.b = args.b
 self.c = args.c
 self.d = args.d
 def method_ab(self):
 return self.a + self.b
 def method_cd(self):
 return self.c + self.d
  […]

 The question is if `args.a`, `args.b`, …, are semantically part of the
 state of the objects or not.  Hard to tell in general.
 
 Would you mind elaborating a little on that first sentence?

Do `self.a`, `self.b`, …, define the state of a `Class_a` instance or 
not?  One can't answer that question without knowing the meaning of the 
class and the attributes.

Ciao,
Marc 'BlackJack' Rintsch
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Re: Instance attributes vs method arguments

On Nov 25, 5:48 pm, John O'Hagan [EMAIL PROTECTED] wrote:
 On Tue, 25 Nov 2008, Marc 'BlackJack' Rintsch wrote:
  On Tue, 25 Nov 2008 07:27:41 +, John O'Hagan wrote:
   Is it better to do this:

   class Class_a():
         def __init__(self, args):
                 self.a = args.a
                 self.b = args.b
                 self.c = args.c
                 self.d = args.d
         def method_ab(self):
                 return self.a + self.b
         def method_cd(self):
                 return self.c + self.d

   or this:

   class Class_b():
         def method_ab(self, args):
                 a = args.a
                 b = args.b
                 return a + b
         def method_cd(self, args)
                 c = args.c
                 d = args.d
                 return c + d

   ?

   Assuming we don't need access to the args from outside the class, is
   there anything to be gained (or lost) by not initialising attributes
   that won't be used unless particular methods are called?

  The question is if `args.a`, `args.b`, …, are semantically part of the
  state of the objects or not.  Hard to tell in general.

 Would you mind elaborating a little on that first sentence?



  I know it's a made up example but in the second class I'd ask myself if
  those methods are really methods, because they don't use `self` so they
  could be as well be functions or at least `staticmethod`\s.

 I guess I went overboard keeping the example simple :) : the real case has
 many methods, and they all use self (except one, actually, so I'm looking
 up static methods now; thanks).

 Regards,

 John

I'm not sure if you are asking a technical question or a design
question. If it helps, I try to think of an object as a thing which
has a job to do. If the 'thing' needs information every time to define
what it is, or give it a starting state, then that is an argument of
__init__() . If I want the object to change or handle something which
is a logical task of 'thing', then I give it what it needs via
properties or methods (I find I almost never use public instance
attributes, but then again I am usually writing SDKs which is all
about interface).

Not sure if that helps...

- Rafe
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Re: Getting in to metaprogramming

On Nov 25, 5:41 pm, Aaron Brady [EMAIL PROTECTED] wrote:
 On Nov 25, 4:08 am, Rafe [EMAIL PROTECTED] wrote:

  Hi,

  In the name of self-education can anyone share some pointers, links,
  modules, etc that I might use to begin learning how to do some
  metaprogramming. That is, using code to write code (right?)

  Cheers,

  - Rafe

 Python programs can generate code for themselves.

  for i in range( 10 ):

 ...   d= { 'cls': i }
 ...   s=
 ... class Cls%(cls)s:
 ...   def meth%(cls)s( self, arg ):
 ...     print 'in meth%(cls)s, arg:', arg
 ... % d
 ...   exec( s )
 ...   s= 
 ... inst%(cls)s= Cls%(cls)s()
 ... % d
 ...   exec( s )
 ... inst0.meth0( arg )
 in meth0, arg: arg
  inst1.meth1( arg )
 in meth1, arg: arg
  inst2.meth2( arg )

 in meth2, arg: arg

 The 'Cls0', 'Cls1', 'Cls2' repetitiveness is taken care of with a for-
 loop.

Michele, I am thinking about python which writes python. Which makes
Aaron's post accurate to my needs. More specifically, I am considering
what it might be like to use python to build a script file which can
be executed later. Until now I planned to store info to XML and then
parse it to run later. There are good reasons that generating a script
file would be more useful for me.

Aaron, Is it really as simple as gathering strings of code? Sort of
like generating HTML or XML directly? Is there any other framework or
pattern set that is worth looking in to?

Thanks for helping me explore this.

- Rafe
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Re: Getting in to metaprogramming

2008-11-25 Thread Michele Simionato

On Nov 25, 12:12 pm, Rafe [EMAIL PROTECTED] wrote:
 is it really as simple as gathering strings of code?

Yes.

 Sort of like generating HTML or XML directly? Is there any other framework or
 pattern set that is worth looking in to?

Yes, the compiler module and the ast module in the standard library.
You may also
look at how templating languages that compile to Python code work (I
mean mako
or PTL/qpy). You may find interesting how the import hooks work too.

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Re: Multiple equates

2008-11-25 Thread Iain King

On Nov 17, 7:41 pm, Tim Chase [EMAIL PROTECTED] wrote:
  It doesn't matter as none of this is valid Python. In Python you have to
  write

  array[x1] = False
  array[x2] = False

 Uh...not so much...

a = [1,2,3,4,5]
x1, x2 = 1, 3
a[x1] = a[x2] = False
a
   [1, False, 3, False, 5]

 Works for me.

 To the OP, I think rather than cluttering my code, I'd just
 create a loop

for i in [x1,x2,x3,x4,...x1024]:
  a[i] = False

  From Diez's disassembly of it (as an aside, nifty little intro
 to dis.dis()...thanks, Diez!), it looks like it boils down to is
 DUP_TOP faster than LOAD_CONST because the rest of the
 operations.  At this point, it's pretty nitty-gritty.

 Unless the code is in an inner loop somewhere, the simple loop
 should be more than fast enough.  Without knowing the source of
 the [x1,...] index variables, it's hard to tell if there's a more
 optimal way to do this.

 -tkc

The loop is much nicer, especially as your array gets longer.  The
generic:

for i in xrange(array):
array[i] = False

will set the entire array.

Regarding your original question:

array[x1] = array[x2] = False

array[x1] = False
array[x2] = False

These two blocks are functionally the same when you are setting to
True or False (or any immutable), but are not if  setting to
immutables, which could give you some real head-scratching bugs if you
were unaware of the difference - the first version assigns the same
object to both names:

 array[x1] = array[x2] = []
 array[x1].append(Hi)
 array[x2]
['Hi']


Iain

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Re: Getting in to metaprogramming

2008-11-25 Thread Aaron Brady

On Nov 25, 4:08 am, Rafe [EMAIL PROTECTED] wrote:
 Hi,

 In the name of self-education can anyone share some pointers, links,
 modules, etc that I might use to begin learning how to do some
 metaprogramming. That is, using code to write code (right?)

 Cheers,

 - Rafe

Python programs can generate code for themselves.

 for i in range( 10 ):
...   d= { 'cls': i }
...   s=
... class Cls%(cls)s:
...   def meth%(cls)s( self, arg ):
... print 'in meth%(cls)s, arg:', arg
... % d
...   exec( s )
...   s= 
... inst%(cls)s= Cls%(cls)s()
... % d
...   exec( s )
...
 inst0.meth0( arg )
in meth0, arg: arg
 inst1.meth1( arg )
in meth1, arg: arg
 inst2.meth2( arg )
in meth2, arg: arg

The 'Cls0', 'Cls1', 'Cls2' repetitiveness is taken care of with a for-
loop.
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Re: Multiple equates

2008-11-25 Thread Iain King

On Nov 25, 11:29 am, Iain King [EMAIL PROTECTED] wrote:
 On Nov 17, 7:41 pm, Tim Chase [EMAIL PROTECTED] wrote:



   It doesn't matter as none of this is valid Python. In Python you have to
   write

   array[x1] = False
   array[x2] = False

  Uh...not so much...

 a = [1,2,3,4,5]
 x1, x2 = 1, 3
 a[x1] = a[x2] = False
 a
[1, False, 3, False, 5]

  Works for me.

  To the OP, I think rather than cluttering my code, I'd just
  create a loop

 for i in [x1,x2,x3,x4,...x1024]:
   a[i] = False

   From Diez's disassembly of it (as an aside, nifty little intro
  to dis.dis()...thanks, Diez!), it looks like it boils down to is
  DUP_TOP faster than LOAD_CONST because the rest of the
  operations.  At this point, it's pretty nitty-gritty.

  Unless the code is in an inner loop somewhere, the simple loop
  should be more than fast enough.  Without knowing the source of
  the [x1,...] index variables, it's hard to tell if there's a more
  optimal way to do this.

  -tkc

 The loop is much nicer, especially as your array gets longer.  The
 generic:

 for i in xrange(array):
 array[i] = False

 will set the entire array.

 Regarding your original question:

 array[x1] = array[x2] = False

 array[x1] = False
 array[x2] = False

 These two blocks are functionally the same when you are setting to
 True or False (or any immutable), but are not if  setting to
 immutables, which could give you some real head-scratching bugs if you
 were unaware of the difference - the first version assigns the same
 object to both names:

  array[x1] = array[x2] = []
  array[x1].append(Hi)
  array[x2]

 ['Hi']

 Iain


...and of course, the second time I say 'immutable' I mean 'mutable'.
Hopefully the example was clearer than the text.

Iain
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Re: How to get a directory file descriptor?

2008-11-25 Thread alex23

On Nov 25, 5:05 pm, Cong Ma [EMAIL PROTECTED] wrote:
 Can you give me some hint on getting a directory file descriptor in Python?
 Besides, what's good about os.fchdir() if I can't get a directory fd in the
 first place?

Try: os.open('dirname', os.O_RDONLY)

Check os for a list of the valid flag types.


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Re: How to get a directory file descriptor?

2008-11-25 Thread alex23

On Nov 25, 9:53 pm, alex23 [EMAIL PROTECTED] wrote:
 On Nov 25, 5:05 pm, Cong Ma [EMAIL PROTECTED] wrote:

  Can you give me some hint on getting a directory file descriptor in Python?
  Besides, what's good about os.fchdir() if I can't get a directory fd in the
  first place?

 Try: os.open('dirname', os.O_RDONLY)

 Check os for a list of the valid flag types.

Sorry, that should probably be os.O_DIRECTORY.
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Re: Can't find Python Library packages in Ubuntu (Debian)

2008-11-25 Thread Jerzy Jalocha N

Scott David Daniels wrote:
 So, the first question is: How do I install the complete Python test
 framework under Ubuntu (Debian)?

 You could use BZR or SVN to get a copy of the full Lib/test tree.  Given
 your long-disconnected running, I'd consider getting a full source set
 for release25-maint.
 Note that as of Python 2.6 / 3.0, if Python is not restricted to
 system directories for security reasons (if sys.flags.no_user_site is
 non-0), you may make a directory in your home directory to be searched.

 See   http://docs.python.org/library/site.html
 for details on USER_SITE and USER_BASE.

 That will allow you to place a test subdirectory under site.USER_SITE
 and get to test.test_list (for example) on your python search path.
 Since it is a user-specific location, you can make a tester user with
 the directory in his own space and not worry about affecting the
 standard environment.

Since I already compiled Python 2.6, and am using it basically only for
testing purposes, this won't be necessary, right now. But someday,
Python 2.6 will get released for Debian, and if it doesn't ship with
the tests, I will come back your instructions. - Thanks, Scott!


Paul Boddie wrote:
 I will try to contact whoever is responsible for the packaging of Python
 in Ubuntu (or Debian), and ask them if they are willing to support the
 _complete_ Python release.

 They may already do so, but I'd argue that they could document the
 packages which provide the complete release a bit better if these are
 not already mentioned in /usr/share/doc/python/README.Debian or some
 similar file.

You are right, /usr/share/doc/python2.5/README.Debian
, should contain
that information, but it doesn't.

I already filed a bug in Launchpad, and will move upstream, if necessary.

 By looking at the documentation for the Debian stable source package,
 I did manage to find a list of generated packages:

 http://packages.debian.org/source/etch/python-defaults

 Perhaps one of these contains the test files.

I checked the most obvious packages there manually without success
before posting my question here. I also used apt-file, which searches for
a specific file in _all_ available packages, including not installed ones,
...no success, again.

 Although such files are
 arguably only of use to people building Python, and such people would
 therefore obtain the source package in order to perform the build
 process, there could be some benefit in having a package which
 provides these files separately. For example, one may wish to verify
 the behaviour of an installed version or to test aspects of another
 implementation.

My personal interest in these tests is the following: I was working with
some sequential dictionaries from ActiveState, but experienced problems
with all recipes. I started writing my own test cases, but found somewhere
a reference about test_dict, test_list et al. Using these, I've been able to
fix a few problems. (Even if some test cases are quite difficult to interpret
right now.)

In general, I think that the Python test suite is extrermely valuable, and
should be made more accessible to all users. Especially in combination
with Python's new Abstract Base Classes, They could prove extremely
useful in creating robust classes with standard interfaces. But I digress.

Thank you, Paul!
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Re: Accessing Modification Time of an Outlook Mail in Python

2008-11-25 Thread Iain King

On Nov 25, 5:11 am, [EMAIL PROTECTED]
[EMAIL PROTECTED] wrote:
 Hi all,
I am writing a small application which reads the contents of an
 Outlook Mail using python. I am able to read the contents, subject
 along with senders and receivers of a mail using MAPI objects. But may
 I know how can I get access to the modification time or the
 receiving time of an outlook mail in Python. For the others I have
 used message object of MAPI session. Here I am pasting a sample code
 to get an idea of what am I doing.

 session = Dispatch(MAPI.session)
 session.Logon('outlook')  # MAPI profile name
 inbox = session.Inbox

 print Inbox name is:, inbox.Name
 print Number of messages:, inbox.Messages.Count

 for i in range(inbox.Messages.Count):
 message = inbox.Messages.Item(i + 1)

 objSender = message.Sender.Address
 objRecip = message.Recipients.Item(j+1)

 Now here I want to access the modification time of each mail. And if
 possible if you can guide me to a place where I can get the elements
 of that message object, that would be helpful.

  Please mail back for further information.
 Thanks in advance,
 Venu.

This looks like the API for the Message object:
http://msdn.microsoft.com/en-us/library/ms526130(EXCHG.10).aspx
Looks like you want TimeLastModified

Iain
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Re: Accessing Modification Time of an Outlook Mail in Python

2008-11-25 Thread skip


Venu ... may I know how can I get access to the modification time or
Venu the receiving time of an outlook mail in Python...

I have no idea off the top of my head, but you might want to browse the
SpamBayes Outlook plugin source code for various ways to manipulate Outlook
messages.


http://spambayes.svn.sourceforge.net/viewvc/spambayes/trunk/spambayes/Outlook2000/

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datetime objects and new()

Hi --

 import datetime
 class ts(datetime.datetime):
... foo = 'bar'
... def __new__(cls, s):
... c = super(ts, cls)
... return c.fromtimestamp(s)
...
 t = ts(0)
Traceback (most recent call last):
  File stdin, line 1, in module
  File stdin, line 5, in __new__
TypeError: __new__() takes exactly 2 arguments (9 given)

I don't understand why that happens -- am I correct in assuming that
the call to .fromtimestamp() is picking up on the ts class? Shouldn't
it get the datetime class instead?

(Yes, I am aware of the problems of using datetime and timestamps)

Could some kind soul please enlighten me?

peter.
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Re: initialized list: strange behavior

Jason Scheirer [EMAIL PROTECTED] writes:

 On Nov 24, 10:34 pm, [EMAIL PROTECTED] wrote:
 Hi Python experts! Please explain this behavior:

  nn=3*[[]]
  nn
 [[], [], []]
  mm=[[],[],[]]
  mm

 [[], [], []]

 Up till now, 'mm' and 'nn' look the same, right? Nope!

  mm[1].append(17)
  mm
 [[], [17], []]
  nn[1].append(17)
  nn

 [[17], [17], [17]]

 ???

 Python 2.5 Win XP

 Thanks!

 You're creating three references to the same list with the
 multiplication operator.

There's no need to introduce references: you're creating a list with the
same object at each position.

[...]
 Python is pass-by-reference, not pass-by-value.

It's certainly not pass-by-reference, nor is it pass-by-value IMHO.

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Re: initialized list: strange behavior

2008-11-25 Thread Benjamin Kaplan

On Tue, Nov 25, 2008 at 9:23 AM, Arnaud Delobelle [EMAIL PROTECTED]wrote:

 Jason Scheirer [EMAIL PROTECTED] writes:

  On Nov 24, 10:34 pm, [EMAIL PROTECTED] wrote:
  Hi Python experts! Please explain this behavior:
 
   nn=3*[[]]
   nn
  [[], [], []]
   mm=[[],[],[]]
   mm
 
  [[], [], []]
 
  Up till now, 'mm' and 'nn' look the same, right? Nope!
 
   mm[1].append(17)
   mm
  [[], [17], []]
   nn[1].append(17)
   nn
 
  [[17], [17], [17]]
 
  ???
 
  Python 2.5 Win XP
 
  Thanks!
 
  You're creating three references to the same list with the
  multiplication operator.

 There's no need to introduce references: you're creating a list with the
 same object at each position.

 [...]
  Python is pass-by-reference, not pass-by-value.

 It's certainly not pass-by-reference, nor is it pass-by-value IMHO.


Please don't get into this here. We have enough threads for this already.




 --
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Re: How to get a directory file descriptor?

2008-11-25 Thread D'Arcy J.M. Cain

On Tue, 25 Nov 2008 16:02:56 +0800
Cong Ma [EMAIL PROTECTED] wrote:
  Can you give me some hint on getting a directory file descriptor in Python?
  for each in os.listdir(os.getcwd()):
print each
 Your code fetches a bunch of strings representing file names in the working
 directory, which is fine. But what I want is something like an integer file
 descriptor, like the one returned by os.open() for files, or the Linux dirfd()
 call, which returns an integer for a pointer to a DIR stream.

Is this what you want?

ofiles = [open(x) for x in os.listdir(os.getcwd())]

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Re: initialized list: strange behavior

2008-11-25 Thread Steve Holden

Arnaud Delobelle wrote:
 Jason Scheirer [EMAIL PROTECTED] writes:
 
 On Nov 24, 10:34 pm, [EMAIL PROTECTED] wrote:
 Hi Python experts! Please explain this behavior:

 nn=3*[[]]
 nn
 [[], [], []]
 mm=[[],[],[]]
 mm
 [[], [], []]

 Up till now, 'mm' and 'nn' look the same, right? Nope!

 mm[1].append(17)
 mm
 [[], [17], []]
 nn[1].append(17)
 nn
 [[17], [17], [17]]

 ???

 Python 2.5 Win XP

 Thanks!
 You're creating three references to the same list with the
 multiplication operator.
 
 There's no need to introduce references: you're creating a list with the
 same object at each position.
 
 [...]
 Python is pass-by-reference, not pass-by-value.
 
 It's certainly not pass-by-reference, nor is it pass-by-value IMHO.
 
Since no lists are being passed as arguments in these examples it's not
pass-by-anything. Jump off that horse right now!

regards
 Steve
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Re: datetime objects and new()

2008-11-25 Thread Peter Otten

peter wrote:

 import datetime
 class ts(datetime.datetime):
 ... foo = 'bar'
 ... def __new__(cls, s):
 ... c = super(ts, cls)
 ... return c.fromtimestamp(s)
 ...
 t = ts(0)
 Traceback (most recent call last):
   File stdin, line 1, in module
   File stdin, line 5, in __new__
 TypeError: __new__() takes exactly 2 arguments (9 given)
 
 I don't understand why that happens -- am I correct in assuming that
 the call to .fromtimestamp() is picking up on the ts class? Shouldn't
 it get the datetime class instead?
 
 (Yes, I am aware of the problems of using datetime and timestamps)
 
 Could some kind soul please enlighten me?

If the datetime class were implemented in Python the fromtimestamp() method
could look like:

@classmethod
def fromtimestamp(cls, s):
year, month, day,... = ...
return cls(year, month, day,...)

This will fail since you modified the constructor to accept only a single
argument.

Peter
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SWIG vs. ctypes (Was: ANN: PyEnchant 1.5.0)

2008-11-25 Thread Roy Smith

In article [EMAIL PROTECTED],
 Ryan Kelly [EMAIL PROTECTED] wrote:

 * Migrated from SWIG to ctypes for the C binding:

Ryan,

I'm looking at a doing a Python wrapper for a C++ library.  We've already 
done a Perl wrapper for this library using SWIG (I wasn't personally 
involved in that effort).  I'm debating whether I should do the Python 
version with SWIG or ctypes.  I'd be interested to hear about your 
experiences with both and why you switched.
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Re: datetime objects and new()

On Nov 25, 3:46 pm, Peter Otten [EMAIL PROTECTED] wrote:
 peter wrote:
  import datetime
  class ts(datetime.datetime):
  ...     foo = 'bar'
  ...     def __new__(cls, s):
  ...         c = super(ts, cls)
  ...         return c.fromtimestamp(s)
  ...
  t = ts(0)
  Traceback (most recent call last):
    File stdin, line 1, in module
    File stdin, line 5, in __new__
  TypeError: __new__() takes exactly 2 arguments (9 given)

  I don't understand why that happens -- am I correct in assuming that
  the call to .fromtimestamp() is picking up on the ts class? Shouldn't
  it get the datetime class instead?

  (Yes, I am aware of the problems of using datetime and timestamps)

  Could some kind soul please enlighten me?

 If the datetime class were implemented in Python the fromtimestamp() method
 could look like:

 @classmethod
 def fromtimestamp(cls, s):
     year, month, day,... = ...
     return cls(year, month, day,...)

 This will fail since you modified the constructor to accept only a single
 argument.

Hm, I had hoped that using super() would result in calling the
constructor of the superclass, ie. datetime. Did I use super() wrong?

Thanks,
peter.


 Peter

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any body know how to use winlike

2008-11-25 Thread Anuradha Jena

Hi,
  Any body know how to use winlike.If yes.Can s/he give a simple example
of onEvent  onClose functionally.  Actually i am facing problem where.
  I have one page there if u click on a text Winlike window will
open.After opening i want to print text value,it is not printing.i am
calling by parent.document.forms['formname'].getElementById(Id).
  parent.document.forms is giving an object but
parent.document.forms['formname'] is giving undefined.I already tired all
the possibility like opener/parent.window .So can anybody give any solution?

Thanks
Anuradha

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Re: SWIG vs. ctypes (Was: ANN: PyEnchant 1.5.0)

2008-11-25 Thread skip


Roy I'm debating whether I should do the Python version with SWIG or
Roy ctypes. 

Unless your C++ library exports a C api I don't think you can use ctypes to
make it available within Python.

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Re: initialized list: strange behavior

2008-11-25 Thread alexander . genkin

The issue is exhausted in Python Library Reference, Chapter 3.6, so I
should apologize for initial posting. All comments were helpful,
though Arnaud and Steve are right that pass-by-anything is off the
point.

Thanks All!

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Re: SWIG vs. ctypes (Was: ANN: PyEnchant 1.5.0)

Roy Smith wrote:

 In article [EMAIL PROTECTED],
  Ryan Kelly [EMAIL PROTECTED] wrote:
 
 * Migrated from SWIG to ctypes for the C binding:
 
 Ryan,
 
 I'm looking at a doing a Python wrapper for a C++ library.  We've already
 done a Perl wrapper for this library using SWIG (I wasn't personally
 involved in that effort).  I'm debating whether I should do the Python
 version with SWIG or ctypes.  I'd be interested to hear about your
 experiences with both and why you switched.

You can't use ctypes for C++, only for C-style APIs.

Diez
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Re: datetime objects and new()

2008-11-25 Thread Peter Otten

peter wrote:

 On Nov 25, 3:46 pm, Peter Otten [EMAIL PROTECTED] wrote:
 peter wrote:
  import datetime
  class ts(datetime.datetime):
  ...     foo = 'bar'
  ...     def __new__(cls, s):
  ...         c = super(ts, cls)
  ...         return c.fromtimestamp(s)
  ...
  t = ts(0)
  Traceback (most recent call last):
  File stdin, line 1, in module
  File stdin, line 5, in __new__
  TypeError: __new__() takes exactly 2 arguments (9 given)

  I don't understand why that happens -- am I correct in assuming that
  the call to .fromtimestamp() is picking up on the ts class? Shouldn't
  it get the datetime class instead?

  (Yes, I am aware of the problems of using datetime and timestamps)

  Could some kind soul please enlighten me?

 If the datetime class were implemented in Python the fromtimestamp()
 method could look like:

 @classmethod
 def fromtimestamp(cls, s):
 year, month, day,... = ...
 return cls(year, month, day,...)

 This will fail since you modified the constructor to accept only a single
 argument.
 
 Hm, I had hoped that using super() would result in calling the
 constructor of the superclass, ie. datetime. Did I use super() wrong?
 
 Thanks,
 peter.

Sorry, I didn't pay the necessary attention. 

I've only used super() with normal methods, but as

 from datetime import *
 class TS(datetime):
... def __new__(cls, ts):
... return datetime.fromtimestamp(ts)
...
 TS(0)
datetime.datetime(1970, 1, 1, 1, 0)

works super() would be the most likely culprit.

Peter

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end of print = lower productivity ?

I want my productivity back.

In Python 2.x, I could easily write things like -- print f / print
add / print done -- to a lot of different places in my code, which
allowed me to find bugs that I could not track otherwise. When I found
out that f was not at fault, I could write -- print g -- to some
other place... etc, so that a significant part of the time spent
debugging was actually used to write print statements.

Now the print statement disappeared, and I have to write print(f)
instead. These parentheses not only take time to write, they also make
me think twice about using print for debugging purposes. Pressing 
SHIFT  then  (  thenmakes the whole process quite a hassle.

I agree with most of the arguments that have been made against using
the print statement to build code, but I did care about the efficient
debugging tool it was.
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Re: end of print = lower productivity ?

2008-11-25 Thread skip


 Now the print statement disappeared, and I have to write print(f)
 instead. These parentheses not only take time to write, they also make
 me think twice about using print for debugging purposes. Pressing 
 SHIFT  then  (  thenmakes the whole process quite a hassle.

:rollseyes:

I hope there was a missing smiley in that post.  If a couple extra parens
destroys your debugging productivity I suspect you need a fresh approach to
the task.

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Re: end of print = lower productivity ?

[EMAIL PROTECTED] wrote:

 I want my productivity back.
 
 In Python 2.x, I could easily write things like -- print f / print
 add / print done -- to a lot of different places in my code, which
 allowed me to find bugs that I could not track otherwise. When I found
 out that f was not at fault, I could write -- print g -- to some
 other place... etc, so that a significant part of the time spent
 debugging was actually used to write print statements.
 
 Now the print statement disappeared, and I have to write print(f)
 instead. These parentheses not only take time to write, they also make
 me think twice about using print for debugging purposes. Pressing 
 SHIFT  then  (  thenmakes the whole process quite a hassle.
 
 I agree with most of the arguments that have been made against using
 the print statement to build code, but I did care about the efficient
 debugging tool it was.

I used to use print a lot. Once I found

import pdb; pdb.set_trace()

I massively lost interest in it. And gained *much* more debugging
power/productivity.

Also, using logging instead of print allows you to keep the output producing
statements in your code, while turning them on only if things get fishy.

Diez
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Re: datetime objects and new()

On Nov 25, 4:39 pm, Peter Otten [EMAIL PROTECTED] wrote:
 peter wrote:
  On Nov 25, 3:46 pm, Peter Otten [EMAIL PROTECTED] wrote:
  peter wrote:
   import datetime
   class ts(datetime.datetime):
   ...     foo = 'bar'
   ...     def __new__(cls, s):
   ...         c = super(ts, cls)
   ...         return c.fromtimestamp(s)
   ...
   t = ts(0)
   Traceback (most recent call last):
   File stdin, line 1, in module
   File stdin, line 5, in __new__
   TypeError: __new__() takes exactly 2 arguments (9 given)

   I don't understand why that happens -- am I correct in assuming that
   the call to .fromtimestamp() is picking up on the ts class? Shouldn't
   it get the datetime class instead?

   (Yes, I am aware of the problems of using datetime and timestamps)

   Could some kind soul please enlighten me?

  If the datetime class were implemented in Python the fromtimestamp()
  method could look like:

  @classmethod
  def fromtimestamp(cls, s):
  year, month, day,... = ...
  return cls(year, month, day,...)

  This will fail since you modified the constructor to accept only a single
  argument.

  Hm, I had hoped that using super() would result in calling the
  constructor of the superclass, ie. datetime. Did I use super() wrong?

  Thanks,
  peter.

 Sorry, I didn't pay the necessary attention.

 I've only used super() with normal methods, but as

  from datetime import *
  class TS(datetime):

 ...     def __new__(cls, ts):
 ...             return datetime.fromtimestamp(ts)
 ... TS(0)

 datetime.datetime(1970, 1, 1, 1, 0)

 works super() would be the most likely culprit.

Yes, that works, except the returned object is (unsurprisingly) a pure
datetime instance, which means I cannot access any other attributes I
defined on my class.

The docs on super() ( http://docs.python.org/library/functions.html#super
) are a little murky unfortunately.

Cheers,
peter.



 Peter

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Re: initialized list: strange behavior

Steve Holden [EMAIL PROTECTED] writes:

 Arnaud Delobelle wrote:
 Jason Scheirer [EMAIL PROTECTED] writes:
 Python is pass-by-reference, not pass-by-value.
 
 It's certainly not pass-by-reference, nor is it pass-by-value IMHO.
 
 Since no lists are being passed as arguments in these examples it's not
 pass-by-anything. Jump off that horse right now!

You're right that Python's calling semantics have nothing to do with the
question asked.  I just thought best not to leave the OP under any
misapprehension.

-- 
Arnaud
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Re: end of print = lower productivity ?

On Nov 25, 4:44 pm, [EMAIL PROTECTED] wrote:
 I want my productivity back.

 In Python 2.x, I could easily write things like -- print f / print
 add / print done -- to a lot of different places in my code, which
 allowed me to find bugs that I could not track otherwise. When I found
 out that f was not at fault, I could write -- print g -- to some
 other place... etc, so that a significant part of the time spent
 debugging was actually used to write print statements.

 Now the print statement disappeared, and I have to write print(f)
 instead. These parentheses not only take time to write, they also make
 me think twice about using print for debugging purposes. Pressing 
 SHIFT  then  (  thenmakes the whole process quite a hassle.

 I agree with most of the arguments that have been made against using
 the print statement to build code, but I did care about the efficient
 debugging tool it was.

BUT you now can do

 p = print
 p(f)

Voila, 4 keystrokes saved :-)


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Re: end of print = lower productivity ?

On Nov 25, 4:53 pm, Diez B. Roggisch [EMAIL PROTECTED] wrote:
 I used to use print a lot. Once I found

 import pdb; pdb.set_trace()

 I massively lost interest in it. And gained *much* more debugging
 power/productivity.

In some cases, this is not discriminatory enough : there are simply
too many function calls.
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Re: How to get a directory file descriptor?

2008-11-25 Thread Baptiste Carvello


Cong Ma a écrit :

Dear all,

Can you give me some hint on getting a directory file descriptor in Python?
Besides, what's good about os.fchdir() if I can't get a directory fd in the
first place?

Thanks for your reply.

Regards,
Cong.

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Hello,

I believe you want os.open :

Python 2.5.2 (r252:60911, Sep 29 2008, 21:10:35)
[GCC 4.3.2] on linux2
Type help, copyright, credits or license for more information.
 import os
 d=os.open('mydir',os.O_RDONLY)
 d
3
 os.fchdir(d)
 os.getcwd()
'/home/baptiste/mydir'


Cheers,
Baptiste

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Re: datetime objects and new()

2008-11-25 Thread Peter Otten

peter wrote:

  from datetime import *
  class TS(datetime):

 ...     def __new__(cls, ts):
 ...             return datetime.fromtimestamp(ts)
 ... TS(0)

 datetime.datetime(1970, 1, 1, 1, 0)

 works super() would be the most likely culprit.
 
 Yes, that works, except the returned object is (unsurprisingly) a pure
 datetime instance, which means I cannot access any other attributes I
 defined on my class.

How about

import datetime

class DT(datetime.datetime):
def __new__(cls, *args):
if len(args) == 1:
return cls.fromtimestamp(args[0])
return datetime.datetime.__new__(cls, *args)

then?

Peter
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Re: end of print = lower productivity ?

On Nov 25, 5:05 pm, peter [EMAIL PROTECTED] wrote:
 BUT you now can do

  p = print
  p(f)

 Voila, 4 keystrokes saved :-)

All right. Let's talk about that.

When I write print, it is both effortless and instantaneous : my
hands do not move, a wave goes through my fingers, it all happens in a
tenth of a second.

Contrast this with what one has to go through to catch the SHIFT key,
and then the ( : move the left hand, press SHIFT, move the right
hand, aim (, press, miss, press again. Same thing at the end of the
function call.

I know it sounds ridiculous, but it does *impair* my debugging
productivity. Taylor would agree.
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Re: end of print = lower productivity ?

2008-11-25 Thread Johannes Bauer

[EMAIL PROTECTED] schrieb:

 I know it sounds ridiculous

Not only that - it also sounds as if there's spring break in Trollland.

Regards,
Johannes

-- 
Meine Gegenklage gegen dich lautet dann auf bewusste Verlogenheit,
verlästerung von Gott, Bibel und mir und bewusster Blasphemie.
 -- Prophet und Visionär Hans Joss aka HJP in de.sci.physik
 [EMAIL PROTECTED]
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Re: SWIG vs. ctypes (Was: ANN: PyEnchant 1.5.0)

On Nov 25, 4:34 pm, Diez B. Roggisch [EMAIL PROTECTED] wrote:

 You can't use ctypes for C++, only for C-style APIs.

 Diez

With some work, you can convert your C++ objects to PyObject* and then
return the latter in a function with C bindings.
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Reg Expression - Get position of

2008-11-25 Thread M_H


Hey,

I need the position of the last char 

Let's say I have a string
mystr =  mimetype=text/htmlcontent![CDATA[

I need the posistion of the  (second sign) - so I can cut away the
first part.

The problem is that it can be like  but also like   or  

But it is def the quotes and the closing brakets.

How do I get the position of the   

Hope you can help,
Bacco


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confused about classes and tkinter object design

2008-11-25 Thread marc wyburn

Hi,

I've created my first Tkinter GUI class which consists of some buttons
that trigger functions.  I have also created a
tkFileDialog.askdirectory control to local a root folder for log
files.

I have several file paths that depend on the value of
tkFileDialog.askdirectory should I create an object that inherits this
value or can I point functions at the GUI class?

I am creating the tkinter GUI instance using;

if __name__ == __main__:
GUI = AuditorGUI()
GUI.mainloop()

class AuditorGUI(Frame):
def __init__(self):
Frame.__init__(self)
self.pack(expand = YES, fill = BOTH)

##  Create GUI objects

self.currentdir = StringVar()
self.currentdir.set(os.getcwd())

self.logdir = Button(self, text=Choose Data
directory,command=self.choose_dir)
self.logdir.grid(row=1,column=0,sticky='nsew',pady=20,padx=20)

self.labeldirpath = Label(self, textvariable=self.currentdir)

def choose_dir(self):
dirname = tkFileDialog.askdirectory
(parent=self,initialdir=self.currentdir.get(),title='Please select a
directory')
if len(dirname )  0:
self.currentdir.set(dirname)

I think I have created an instance of the AuditorGUI class called GUI
so should be able to access the path using GUI.currentdir but this
doesn't work.

I'm still struggling with classes so not sure whether my problem is
tkinter related or not.

Thanks, MW

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Re: end of print = lower productivity ?

2008-11-25 Thread Tim Chase


p = print
p(f)

Voila, 4 keystrokes saved :-)


When I write print, it is both effortless and instantaneous : my
hands do not move, a wave goes through my fingers, it all happens in a
tenth of a second.

Contrast this with what one has to go through to catch the SHIFT key,
and then the ( : move the left hand, press SHIFT, move the right
hand, aim (, press, miss, press again. Same thing at the end of the
function call.

I know it sounds ridiculous, but it does *impair* my debugging
productivity. Taylor would agree.


It's not so much rediculous as a failure of your editor to 
assist you.  In Vim (my editor-of-choice), I'd do something like


  :iab print print()leftbs

and that's the end of it.  Or you could be even lazier if you 
don't name your variables p:


  :iab p print()left

in which case you can just type

  p

and it automatically populates with

  print()

with the cursor after the double-quote ready for you to type the 
string's contents.  Net gain:  5 characters in old-Python and 6 
characters in new-Python ;-)


Any editor environment worth its salt should allow you to do 
things like this (insert abreviated text or template text).  The 
gains made from making print a function far outweigh niggling 
things that simple editor-tweaks can overcome.


-tkc






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Re: Instance attributes vs method arguments


M.-A. Lemburg a écrit :
(snip)

It is always good practice to provide default values for
instance variables in the class definition, both to enhance
readability and to allow adding documentation regarding
the variables, e.g.


Your opinion. As far as I'm concerned, using class variables this way is 
more of a WTF than a good practice.



class Class_a:

   # Foo bar
   a = None

   # Foo baz
   b = None

   ...


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Re: datetime objects and new()

On Nov 25, 5:16 pm, Peter Otten [EMAIL PROTECTED] wrote:
 peter wrote:
   from datetime import *
   class TS(datetime):

  ...     def __new__(cls, ts):
  ...             return datetime.fromtimestamp(ts)
  ... TS(0)

  datetime.datetime(1970, 1, 1, 1, 0)

  works super() would be the most likely culprit.

  Yes, that works, except the returned object is (unsurprisingly) a pure
  datetime instance, which means I cannot access any other attributes I
  defined on my class.

 How about

 import datetime

 class DT(datetime.datetime):
     def __new__(cls, *args):
         if len(args) == 1:
             return cls.fromtimestamp(args[0])
         return datetime.datetime.__new__(cls, *args)

 then?

A bit hacky, but does the trick quite nicely otherwise -- thanks :-)

Still, I wonder whats up with super(). Obviously I must be missing
something here.

peter.



 Peter

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Re: SWIG vs. ctypes (Was: ANN: PyEnchant 1.5.0)

2008-11-25 Thread Olivier Grisel

2008/11/25  [EMAIL PROTECTED]:
 On Nov 25, 4:34 pm, Diez B. Roggisch [EMAIL PROTECTED] wrote:

 You can't use ctypes for C++, only for C-style APIs.

 Diez

 With some work, you can convert your C++ objects to PyObject* and then
 return the latter in a function with C bindings.

http://cython.org also has some support for C++ bindings.

I also heard that Boost.Python is very well suited to make full
featured C++ / python bindings though I never tried myself.

-- 
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encoding

2008-11-25 Thread luca72

hello i'm writing an irc client, i use for encoding the utf-8 but i
never see all the typed sign in the correct way, anyone know the
standard encodind for the irc channels?

Regards

Luca
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Enumerating k-segmentations of a sequence

2008-11-25 Thread bullockbefriending bard

I'm not sure if my terminology is precise enough, but what I want to
do is:

Given an ordered sequence of n items, enumerate all its possible k-
segmentations.

This is *not* the same as enumerating the k set partitions of the n
items because I am only interested in those set partitions which
preserve the order of the items. i.e. if the input sequence is (1 2 3
4 5), then ((1 4) (2 3) (5)) is unacceptable, whereas ((1 2) (3) (4
5)) is acceptable. Hence use of term 'segmentations'.

e.g., for input sequence (1 2 3 4 5) and k = 3, I need a function
which enumerates the following 3-segmentations:

((1 2 3) (4) (5))
((1 2) (3 4) (5))
((1 2) (3) (4 5))
((1) (2 3 4) (5))
((1) (2 3) (4 5))
((1) (2) (3 4 5))

The reason I want to do this is to use it in some simple one-
dimensional clustering, i.e. each set item (won't be just integers as
above) will have a value of interest, and i'll select the particular
set partition which minimises Sigma SSD (sum of squared differences
from mean) of these values.

It seems overkill to generate the full list of set partitions
[including e.g. ((1 4) (2) (3 5))] because I intend to begin by
sorting the input sequence such that element 1  element 2  ... 
element n.

Structural Recursion not being my strong point, any ideas on how to go
about this would be much appreciated!

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Re: encoding

2008-11-25 Thread Benjamin Kaplan

On Tue, Nov 25, 2008 at 11:53 AM, luca72 [EMAIL PROTECTED] wrote:

 hello i'm writing an irc client, i use for encoding the utf-8 but i
 never see all the typed sign in the correct way, anyone know the
 standard encodind for the irc channels?

 Regards

 Luca
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This is something where Google is very helpful. I haven't dealt with this
before, but a look at the definition of the protocol says there isn't any
standard encoding. As a matter of fact, the RFC specifically says there is
no standard character set[1]. The only thing it specifies is that IRC uses
an 8-bit protocol. Since UTF-8 that doesn't work, I'd try using ISO-8859 and
CP1252 and see if those work better.

[1] http://www.faqs.org/rfcs/rfc1459.html (section 2.2)
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Re: Enumerating k-segmentations of a sequence

2008-11-25 Thread marek . rocki

bullockbefriending bard napisał(a):
 I'm not sure if my terminology is precise enough, but what I want to
 do is:

 Given an ordered sequence of n items, enumerate all its possible k-
 segmentations.

 This is *not* the same as enumerating the k set partitions of the n
 items because I am only interested in those set partitions which
 preserve the order of the items. i.e. if the input sequence is (1 2 3
 4 5), then ((1 4) (2 3) (5)) is unacceptable, whereas ((1 2) (3) (4
 5)) is acceptable. Hence use of term 'segmentations'.

 e.g., for input sequence (1 2 3 4 5) and k = 3, I need a function
 which enumerates the following 3-segmentations:

 ((1 2 3) (4) (5))
 ((1 2) (3 4) (5))
 ((1 2) (3) (4 5))
 ((1) (2 3 4) (5))
 ((1) (2 3) (4 5))
 ((1) (2) (3 4 5))

 The reason I want to do this is to use it in some simple one-
 dimensional clustering, i.e. each set item (won't be just integers as
 above) will have a value of interest, and i'll select the particular
 set partition which minimises Sigma SSD (sum of squared differences
 from mean) of these values.

 It seems overkill to generate the full list of set partitions
 [including e.g. ((1 4) (2) (3 5))] because I intend to begin by
 sorting the input sequence such that element 1  element 2  ... 
 element n.

 Structural Recursion not being my strong point, any ideas on how to go
 about this would be much appreciated!

I'm not sure if I correctly understood the semantics of what you need.
Anyway it looks like a nice exercise in nested generators:

def segmentations(sequence, k):
assert 1 = k = len(sequence)
if k == 1:
yield [sequence]
else:
for headlen in xrange(1, len(sequence) - k + 2):
head, tail = sequence[:headlen], sequence[headlen:]
for tail_seg in segmentations(tail, k - 1):
yield [head] + tail_seg

for segmentation in segmentations((1, 2, 3, 4, 5), 3):
print segmentation

Regards,
Marek
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Re: end of print = lower productivity ?

2008-11-25 Thread George Sakkis

On Nov 25, 10:52 am, [EMAIL PROTECTED] wrote:
      Now the print statement disappeared, and I have to write print(f)
      instead. These parentheses not only take time to write, they also make
      me think twice about using print for debugging purposes. Pressing 
      SHIFT  then  (  thenmakes the whole process quite a hassle.

 :rollseyes:

 I hope there was a missing smiley in that post.  If a couple extra parens
 destroys your debugging productivity I suspect you need a fresh approach to
 the task.

Seconded; I thought he's either joking or trolling.

George
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Re: end of print = lower productivity ?

[EMAIL PROTECTED] wrote:

 On Nov 25, 4:53 pm, Diez B. Roggisch [EMAIL PROTECTED] wrote:
 I used to use print a lot. Once I found

 import pdb; pdb.set_trace()

 I massively lost interest in it. And gained *much* more debugging
 power/productivity.
 
 In some cases, this is not discriminatory enough : there are simply
 too many function calls.

But not to many prints with to few parentheses? You must be joking. 

Diez
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Re: encoding

2008-11-25 Thread Dotan Cohen

2008/11/25 Benjamin Kaplan [EMAIL PROTECTED]:
On Tue, Nov 25, 2008 at 11:53 AM, luca72 [EMAIL PROTECTED] wrote:

hello i'm writing an irc client, i use for encoding the utf-8 but i
never see all the typed sign in the correct way, anyone know the
standard encodind for the irc channels?

Regards

Luca
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This is something where Google is very helpful. I haven't dealt with this
before, but a look at the definition of the protocol says there isn't any
standard encoding. As a matter of fact, the RFC specifically says there is
no standard character set[1]. The only thing it specifies is that IRC uses
an 8-bit protocol. Since UTF-8 that doesn't work, I'd try using ISO-8859 and
CP1252 and see if those work better.

[1] http://www.faqs.org/rfcs/rfc1459.html (section 2.2)

In any case I would suggest that you use UTF-8 anyway. You will save
your users a lot of headaches. While I am a big standards nut, this is
the use case where you should divert.

--
Dotan Cohen

http://what-is-what.com
http://gibberish.co.il

א-ב-ג-ד-ה-ו-ז-ח-ט-י-ך-כ-ל-ם-מ-ן-נ-ס-ע-ף-פ-ץ-צ-ק-ר-ש-ת
ا-ب-ت-ث-ج-ح-خ-د-ذ-ر-ز-س-ش-ص-ض-ط-ظ-ع-غ-ف-ق-ك-ل-م-ن-ه‍-و-ي
А-Б-В-Г-Д-Е-Ё-Ж-З-И-Й-К-Л-М-Н-О-П-Р-С-Т-У-Ф-Х-Ц-Ч-Ш-Щ-Ъ-Ы-Ь-Э-Ю-Я
а-б-в-г-д-е-ё-ж-з-и-й-к-л-м-н-о-п-р-с-т-у-ф-х-ц-ч-ш-щ-ъ-ы-ь-э-ю-я
ä-ö-ü-ß-Ä-Ö-Ü
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Re: Using dictionary to hold regex patterns?

2008-11-25 Thread Thomas Mlynarczyk


John Machin schrieb:


No, complicated is more related to unused features. In
the case of using an aeroplane to transport 3 passengers 10 km along
the autobahn, you aren't using the radar, wheel-retractability, wings,
pressurised cabin, etc. In your original notion of using a dict in
your lexer, you weren't using the mapping functionality of a dict at
all. In both cases you have perplexed bystanders asking Why use a
plane/dict when a car/list will do the job?.


Now the matter is getting clearer in my head.

Thanks and greetings,
Thomas

--
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(Coluche)
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Re: Enumerating k-segmentations of a sequence

2008-11-25 Thread Mark Dickinson

On Nov 25, 4:56 pm, bullockbefriending bard [EMAIL PROTECTED]
wrote:
 I'm not sure if my terminology is precise enough, but what I want to
 do is:
 [snip problem description]
 Structural Recursion not being my strong point, any ideas on how to go
 about this would be much appreciated!

If you have Python 2.6 available, itertools.combination might be
useful.
Here's an example:

from itertools import combinations

def partitions(l, k):
generate all partitions of a list l into k nonempty pieces
n = len(l)
for c in combinations(range(1, n), k-1):
c = [0] + list(c) + [n]
yield [l[c[i]:c[i+1]] for i in xrange(k)]

for p in partitions(range(1, 6), 3):
print p


Mark
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Re: Enumerating k-segmentations of a sequence

2008-11-25 Thread Mark Dickinson

On Nov 25, 5:34 pm, Mark Dickinson [EMAIL PROTECTED] wrote:
 If you have Python 2.6 available, itertools.combination might be

That should be itertools.combinations, of course.

The idea is that to give a partition of e.g., a 5-element list
into 3 nonempty pieces, all you have to do is say where to break
the list.  There are 4 possible places to break (between the
1st and 2nd elements, 2nd and 3rd, etc.), and you've got to
make two breaks.  Then combinations(range(1, 5), 2) generates
all possible pairs of breaking points.

Mark
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Re: Enumerating k-segmentations of a sequence

2008-11-25 Thread bearophileHUGS

My version:

from itertools import combinations as xcombinations
from itertools import izip, islice

def xpairwise(iterable):
# docs and doctests removed
return izip(iterable, islice(iterable, 1, None))

def segmentations(seq, k):
for comb in xcombinations(range(1, len(seq)), k-1):
yield [seq[start:stop] for start,stop in xpairwise((None,) +
comb + (None,))]

for seg in segmentations(range(1, 6), 3):
print seg
print

for seg in segmentations(range(1, 7), 2):
print seg
print

for seg in segmentations(range(1, 7), 3):
print seg
print

for seg in segmentations(range(1, 7), 4):
print seg
print

Other people have already explained how this works.

Bye,
bearophile
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Re: end of print = lower productivity ?

Tim Chase [EMAIL PROTECTED] writes:

 p = print
 p(f)
 Voila, 4 keystrokes saved :-)

 When I write print, it is both effortless and instantaneous : my
 hands do not move, a wave goes through my fingers, it all happens in a
 tenth of a second.

 Contrast this with what one has to go through to catch the SHIFT key,
 and then the ( : move the left hand, press SHIFT, move the right
 hand, aim (, press, miss, press again. Same thing at the end of the
 function call.

 I know it sounds ridiculous, but it does *impair* my debugging
 productivity. Taylor would agree.

 It's not so much rediculous as a failure of your editor to assist
 you.  In Vim (my editor-of-choice), I'd do something like

   :iab print print()leftbs

Or if you had chosen Emacs for editing, you could add the following to
your .emacs.

(fset 'py3kprint
   [?p ?r ?i ?n ?t ?( ?) left])

(add-hook 'python-mode-hook 
  '(lambda () (define-key python-mode-map \C-cp 'py3kprint)))

When in Python mode, it would bind C-c p to the same.

(Warning - I am not an emacs lisp pro!)

-- 
Arnaud
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Re: Getting in to metaprogramming

2008-11-25 Thread Stef Mientki


Rafe wrote:

On Nov 25, 5:41 pm, Aaron Brady [EMAIL PROTECTED] wrote:
  

On Nov 25, 4:08 am, Rafe [EMAIL PROTECTED] wrote:



Hi,
  
In the name of self-education can anyone share some pointers, links,

modules, etc that I might use to begin learning how to do some
metaprogramming. That is, using code to write code (right?)
  
Cheers,
  
- Rafe
  

Python programs can generate code for themselves.



for i in range( 10 ):
  

...   d= { 'cls': i }
...   s=
... class Cls%(cls)s:
...   def meth%(cls)s( self, arg ):
... print 'in meth%(cls)s, arg:', arg
... % d
...   exec( s )
...   s= 
... inst%(cls)s= Cls%(cls)s()
... % d
...   exec( s )
... inst0.meth0( arg )
in meth0, arg: arg


inst1.meth1( arg )
  

in meth1, arg: arg


inst2.meth2( arg )
  

in meth2, arg: arg

The 'Cls0', 'Cls1', 'Cls2' repetitiveness is taken care of with a for-
loop.



Michele, I am thinking about python which writes python. Which makes
Aaron's post accurate to my needs. More specifically, I am considering
what it might be like to use python to build a script file which can
be executed later. Until now I planned to store info to XML and then
parse it to run later. There are good reasons that generating a script
file would be more useful for me.
  
I use Python's own triple quoted string as a generator for the GUI, like 
this:

   GUI = 
   self.NB   ,wx.Notebook ,style = wx.NO_BORDER
 self.Grid   ,Base_Table_Grid ,None, data_values, data_types, data_defs
 Panel2  ,PanelVer, 11,name  = Page2
   list1 ,wx.ListCtrl ,style = wx.LC_REPORT
   
cheers,
Stef

Aaron, Is it really as simple as gathering strings of code? Sort of
like generating HTML or XML directly? Is there any other framework or
pattern set that is worth looking in to?

Thanks for helping me explore this.

- Rafe
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Re: SWIG vs. ctypes (Was: ANN: PyEnchant 1.5.0)

2008-11-25 Thread Matthieu Brucher

Boost.Python is difficult to understand, far more than SWIG. It may be
faster, but I don't think it is worth it ATM.
Binding C++ classes with SWIG is really simple.

Matthieu

2008/11/25 Olivier Grisel [EMAIL PROTECTED]:
 2008/11/25  [EMAIL PROTECTED]:
 On Nov 25, 4:34 pm, Diez B. Roggisch [EMAIL PROTECTED] wrote:

 You can't use ctypes for C++, only for C-style APIs.

 Diez

 With some work, you can convert your C++ objects to PyObject* and then
 return the latter in a function with C bindings.

 http://cython.org also has some support for C++ bindings.

 I also heard that Boost.Python is very well suited to make full
 featured C++ / python bindings though I never tried myself.

 --
 Olivier
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-- 
Information System Engineer, Ph.D.
Website: http://matthieu-brucher.developpez.com/
Blogs: http://matt.eifelle.com and http://blog.developpez.com/?blog=92
LinkedIn: http://www.linkedin.com/in/matthieubrucher
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Re: Enumerating k-segmentations of a sequence

bullockbefriending bard [EMAIL PROTECTED] writes:

 I'm not sure if my terminology is precise enough, but what I want to
 do is:

 Given an ordered sequence of n items, enumerate all its possible k-
 segmentations.

 This is *not* the same as enumerating the k set partitions of the n
 items because I am only interested in those set partitions which
 preserve the order of the items. i.e. if the input sequence is (1 2 3
 4 5), then ((1 4) (2 3) (5)) is unacceptable, whereas ((1 2) (3) (4
 5)) is acceptable. Hence use of term 'segmentations'.

 e.g., for input sequence (1 2 3 4 5) and k = 3, I need a function
 which enumerates the following 3-segmentations:

 ((1 2 3) (4) (5))
 ((1 2) (3 4) (5))
 ((1 2) (3) (4 5))
 ((1) (2 3 4) (5))
 ((1) (2 3) (4 5))
 ((1) (2) (3 4 5))

All you need to do is find the 'cutting places'.  Here you are cutting
at 2 places, the first cut has to be in position  0 and the last in
position  5.  That makes 4 potential cutting places: 1, 2, 3, 4.

So you will have 4C2 = 6 2-segmentations of {1, 2, 3, 4, 5} which are
given by the subsets of {1, 2, 3, 4} of size 2, i.e the 2-combinations
of {1, 2, 3, 4}.

Generalising this, if you want to find the k-segmentations of a
sequence of length n, you will have (n-1)C(k-1) of them and their
cutting places will be given by (k-1)-combinations of {1, 2, ..., n-1}.

Generating the k-combinations is a standard problem so we're done!

-- 
Arnaud
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Re: Enumerating k-segmentations of a sequence

2008-11-25 Thread Gerard flanagan


bullockbefriending bard wrote:

I'm not sure if my terminology is precise enough, but what I want to
do is:

Given an ordered sequence of n items, enumerate all its possible k-
segmentations.

This is *not* the same as enumerating the k set partitions of the n
items because I am only interested in those set partitions which
preserve the order of the items. i.e. if the input sequence is (1 2 3
4 5), then ((1 4) (2 3) (5)) is unacceptable, whereas ((1 2) (3) (4
5)) is acceptable. Hence use of term 'segmentations'.

e.g., for input sequence (1 2 3 4 5) and k = 3, I need a function
which enumerates the following 3-segmentations:

((1 2 3) (4) (5))
((1 2) (3 4) (5))
((1 2) (3) (4 5))
((1) (2 3 4) (5))
((1) (2 3) (4 5))
((1) (2) (3 4 5))



What Arnaud said.


def nchoosek( n, k ):
'''
Generate all subsets of S(n) that have k items.
S(n) = {1, 2, 3, ..., n}

 list(nksubsets(3, 2))
[[1, 2], [1, 3], [2, 3]]
'''
m = n - k + 1
indexer = range(0, k)
seq = range(1, k+1)
last = range(m, n+1)
yield seq[:]
while seq != last:
high_value = -1
high_index = -1
for i in indexer:
val = seq[i]
if val  high_value and val  m + i:
high_value = val
high_index = i
for j in range(k - high_index):
seq[j+high_index] = high_value + j + 1
yield seq[:]

#(minimally tested)
def part(n,k):
rng = range(1, n+1)
for comb in nchoosek(n-1,k-1):
comb = [0] + comb + [n]
yield [rng[s:t] for (s,t) in (comb[i:i+2] for i in range(k))]


for item in part(5, 2):
print item

for item in part(5, 3):
print item

G.

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Re: Reg Expression - Get position of

2008-11-25 Thread Chris Rebert

On Tue, Nov 25, 2008 at 8:36 AM, M_H [EMAIL PROTECTED] wrote:

 Hey,

 I need the position of the last char 

 Let's say I have a string
 mystr =  mimetype=text/htmlcontent![CDATA[

 I need the posistion of the  (second sign) - so I can cut away the
 first part.

 The problem is that it can be like  but also like   or  

 But it is def the quotes and the closing brakets.

 How do I get the position of the   

Python 2.6 (r26:66714, Nov 18 2008, 21:48:52)
[GCC 4.0.1 (Apple Inc. build 5484)] on darwin
Type help, copyright, credits or license for more information.
 mystr = 'mimetype=text/htmlcontent![CDATA['
 mystr.rfind('')
30

Cheers,
Chris
-- 
Follow the path of the Iguana...
http://rebertia.com


 Hope you can help,
 Bacco


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pyExcelerator: setting zoom of a worksheet

2008-11-25 Thread Frank


Hi everybody,

I use pyExcelerator and am quite happy with it, except: I cannot find a option 
for setting the zoom of a particular worksheet. I am using pyExcelerator 
0.6.3a which is the latest as far as i know.


I already contacted the developer of pyExcelerator, he says there is a zoom-option 
in Worksheet.py, but it seems not to be there in my version.


Anyone ever worked with it and maybe can help me?

Thanks a lot.

KR,
Frank


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Re: Module Structure/Import Design Problem


Rafe a écrit :

On Nov 20, 2:06 pm, Arnaud Delobelle [EMAIL PROTECTED] wrote:

(snip)


Or (better IMHO) you can make types register themselves with the factory
function (in which case it would have some state so it would make more
sense to make it a factory object).



Can you elaborate on what you mean by 'register' with the factory
function?


I think Arnaud means something like:

# baselib.py
class Base(object):
_registry = {}

@classmethod
def register(cls, subclass):
cls._registry[subclass.__name__] = subclass

@classmethod
def get_class(cls, classname):
return cls._registry[classname]


# typelib.py
from baselib import Base

class Sub(Base):
   pass

Base.register(Sub)





Also...holy [EMAIL PROTECTED], I got a clean import working! I swear I tried 
that
before with unhappy results. I'll carefully try this in my real code.

Is this the right way to impliment the imports?

baselib.py
[1] class BaseClass(object):
[2] def factory(self):
[3] import typelib   # -- import inside function
[4] return typelib.TypeA()



This is one possible way to solve circular imports, but it has some 
drawbacks - mostly, the performance hit of the import statement on each 
call to BaseClass.factory



typelib.py
[1] import baselib   # -- module level import
[2]
[3] class TypeA(baselib.BaseClass):
[4] def __init__(self):
[5] print TypeA : __init__()


import typelib
type = typelib.TypeA()


ot
This shadows the builtin type 'type'. Better to use another name here...
/ot


TypeA : __init__()

another_type = type.factory()

TypeA : __init__()

another_type

typelib.TypeA object at 0x00B45F10
 
I am curious (not directed at Arnaud), why not have an 'include'-like

import  for special cases in python (or do I not understand includes
either?)


In C,  #include somefile.h is a pre-processor statement that does a 
textual inclusion before compilation. Python just doesn't work that way.


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Re: SWIG vs. ctypes (Was: ANN: PyEnchant 1.5.0)


[EMAIL PROTECTED] schrieb:

On Nov 25, 4:34 pm, Diez B. Roggisch [EMAIL PROTECTED] wrote:

You can't use ctypes for C++, only for C-style APIs.

Diez


With some work, you can convert your C++ objects to PyObject* and then
return the latter in a function with C bindings.


Or you use SWIG or SIP or Python::Boost to do that for you with less work.


Diez
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Re: end of print = lower productivity ?


[EMAIL PROTECTED] schrieb:

On Nov 25, 5:05 pm, peter [EMAIL PROTECTED] wrote:

BUT you now can do


p = print
p(f)

Voila, 4 keystrokes saved :-)


All right. Let's talk about that.

When I write print, it is both effortless and instantaneous : my
hands do not move, a wave goes through my fingers, it all happens in a
tenth of a second.

Contrast this with what one has to go through to catch the SHIFT key,
and then the ( : move the left hand, press SHIFT, move the right
hand, aim (, press, miss, press again. Same thing at the end of the
function call.

I know it sounds ridiculous, but it does *impair* my debugging
productivity. Taylor would agree.


If the relative difference between pressing space  ( impairs your 
absolute debugging productivity, it pretty much follows that the latter 
must be very low for such a minimal overhead to make such a difference.


Try learning touchtype. Might increase your debugging, programming  
writing productivity manyfold.


Diez
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Anyone heard of a good Voice Stress Analysis program

2008-11-25 Thread Daniel Folkes

Anyone heard of a good voice stress analysis program that was either:
a) Written in python
b) can be used by python?

It would be a great help to me.

Thanks,
Dan Folkes
http://danfolkes.com
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Re: confused about classes and tkinter object design

On Nov 25, 10:38 am, marc wyburn [EMAIL PROTECTED] wrote:
 Hi,

 I've created my first Tkinter GUI class which consists of some buttons
 that trigger functions.  I have also created a
 tkFileDialog.askdirectory control to local a root folder for log
 files.

 I have several file paths that depend on the value of
 tkFileDialog.askdirectory should I create an object that inherits this
 value or can I point functions at the GUI class?

 I am creating the tkinter GUI instance using;

 if __name__ == __main__:
     GUI = AuditorGUI()
     GUI.mainloop()

 class AuditorGUI(Frame):
     def __init__(self):
         Frame.__init__(self)
         self.pack(expand = YES, fill = BOTH)

 ##      Create GUI objects

         self.currentdir = StringVar()
         self.currentdir.set(os.getcwd())

         self.logdir = Button(self, text=Choose Data
 directory,command=self.choose_dir)
         self.logdir.grid(row=1,column=0,sticky='nsew',pady=20,padx=20)

         self.labeldirpath = Label(self, textvariable=self.currentdir)

     def choose_dir(self):
         dirname = tkFileDialog.askdirectory
 (parent=self,initialdir=self.currentdir.get(),title='Please select a
 directory')
         if len(dirname )  0:
             self.currentdir.set(dirname)

 I think I have created an instance of the AuditorGUI class called GUI
 so should be able to access the path using GUI.currentdir but this
 doesn't work.

 I'm still struggling with classes so not sure whether my problem is
 tkinter related or not.

 Thanks, MW

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Re: zope vs openACS


Stefan Scholl a écrit :

[EMAIL PROTECTED] [EMAIL PROTECTED] wrote:

On Nov 19, 1:50 am, gavino [EMAIL PROTECTED] wrote:

what is nicer about each?

Yes.


And No.


Or maybe ?
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Re: confused about classes and tkinter object design

On Nov 25, 10:38 am, marc wyburn [EMAIL PROTECTED] wrote:
 Hi,

 I've created my first Tkinter GUI class which consists of some buttons
 that trigger functions.  I have also created a
 tkFileDialog.askdirectory control to local a root folder for log
 files.

 I have several file paths that depend on the value of
 tkFileDialog.askdirectory should I create an object that inherits this
 value or can I point functions at the GUI class?

 I am creating the tkinter GUI instance using;

 if __name__ == __main__:
     GUI = AuditorGUI()
     GUI.mainloop()

 class AuditorGUI(Frame):
     def __init__(self):
         Frame.__init__(self)
         self.pack(expand = YES, fill = BOTH)

 ##      Create GUI objects

         self.currentdir = StringVar()
         self.currentdir.set(os.getcwd())

         self.logdir = Button(self, text=Choose Data
 directory,command=self.choose_dir)
         self.logdir.grid(row=1,column=0,sticky='nsew',pady=20,padx=20)

         self.labeldirpath = Label(self, textvariable=self.currentdir)

     def choose_dir(self):
         dirname = tkFileDialog.askdirectory
 (parent=self,initialdir=self.currentdir.get(),title='Please select a
 directory')
         if len(dirname )  0:
             self.currentdir.set(dirname)

 I think I have created an instance of the AuditorGUI class called GUI
 so should be able to access the path using GUI.currentdir but this
 doesn't work.

 I'm still struggling with classes so not sure whether my problem is
 tkinter related or not.

 Thanks, MW

first off i would use a different instance variable besides GUI.
Could be AG or auditorgui.
Also the conditional if len(dirname )  0: could simply be if
dirname:
When you ask for the attribute currentdir are you asking as
GUI.currentdir.get() or GUI.currentdir???
only the second will work with a TKVAR, but there is really no need to
use a TKVAR here. I would simply do:

self.currentdir = None

then you could say:
if GUI.currentdir:
do this()



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Re: How to get the class instance of a passed method ?


Arnaud Delobelle a écrit :
(snip)

.im_self will become example.method.__self__ and in python 3.  But I
can't see the equivalen of .im_class?


At worst, you'll still have example.method.__self__.__class__ !-)
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Re: Reg Expression - Get position of

On Nov 25, 10:36 am, M_H [EMAIL PROTECTED] wrote:
 Hey,

 I need the position of the last char 

 Let's say I have a string
 mystr =  mimetype=text/htmlcontent![CDATA[

 I need the posistion of the  (second sign) - so I can cut away the
 first part.

 The problem is that it can be like  but also like   or      

 But it is def the quotes and the closing brakets.

 How do I get the position of the   

 Hope you can help,
 Bacco

why not just spilt

 mystr =  'mimetype=text/htmlcontent![CDATA['
 mystr.split('', 2)[-1]
'![CDATA['

you don't want to use an re for something like this


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Re: Module Structure/Import Design Problem

Bruno Desthuilliers [EMAIL PROTECTED] writes:

 Rafe a écrit :
 On Nov 20, 2:06 pm, Arnaud Delobelle [EMAIL PROTECTED] wrote:
 (snip)

 Or (better IMHO) you can make types register themselves with the factory
 function (in which case it would have some state so it would make more
 sense to make it a factory object).


 Can you elaborate on what you mean by 'register' with the factory
 function?

 I think Arnaud means something like:

 # baselib.py
 class Base(object):
 _registry = {}

 @classmethod
 def register(cls, subclass):
 cls._registry[subclass.__name__] = subclass

 @classmethod
 def get_class(cls, classname):
 return cls._registry[classname]


 # typelib.py
 from baselib import Base

 class Sub(Base):
pass

 Base.register(Sub)

That's what I meant.  Sorry Rafe I missed your follow-up.

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Re: Problem with writing fast UDP server

2008-11-25 Thread Krzysztof Retel

On Nov 21, 6:55 pm, Greg Copeland [EMAIL PROTECTED] wrote:
 On Nov 21, 11:05 am, Krzysztof Retel [EMAIL PROTECTED]
 wrote:



  On Nov 21, 4:48 pm, Peter Pearson [EMAIL PROTECTED] wrote:

   On Fri, 21 Nov 2008 08:14:19 -0800 (PST), Krzysztof Retel wrote:
I am not sure what do you mean by CPU-bound? How can I find out if I
run it on CPU-bound?

   CPU-bound is the state in which performance is limited by the
   availability of processor cycles.  On a Unix box, you might
   run the top utility and look to see whether the %CPU figure
   indicates 100% CPU use.  Alternatively, you might have a
   tool for plotting use of system resources.

   --
   To email me, substitute nowhere-spamcop, invalid-net.

  Thanks. I run it without CPU-bound

 With clearer eyes, I did confirm my math above is correct. I don't
 have a networking reference to provide. You'll likely have some good
 results via Google. :)

 If you are not CPU bound, you are likely IO-bound. That means you
 computer is waiting for IO to complete - likely on the sending side.
 In this case, it likely means you have reached your ethernet bandwidth
 limits available to your computer. Since you didn't correct me when I
 assumed you're running 10Mb ethernet, I'll continue to assume that's a
 safe assumption. So, assuming you are running on 10Mb ethernet, try
 converting your application to use TCP. I'd bet, unless you have
 requirements which prevent its use, you'll suddenly have enough
 bandwidth (in this case, frames) to achieve your desired results.

 This is untested and off the top of my head but it should get you
 pointed in the right direction pretty quickly. Make the following
 changes to the server:

 sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  to
 sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

 Make this:
 print Waiting for first packet to arrive...,
 sock.recvfrom(BUFSIZE)

 look like:
 print Waiting for first packet to arrive...,
 cliSock = sock.accept()

 Change your calls to sock.recvfrom(BUFSIZE) to cliSock.recv(BUFSIZE).
 Notice the change to cliSock.

 Keep in mind TCP is stream based, not datagram based so you may need
 to add additional logic to determine data boundaries for re-assemble
 of your data on the receiving end. There are several strategies to
 address that, but for now I'll gloss it over.

 As someone else pointed out above, change your calls to time.clock()
 to time.time().

 On your client, make the following changes.
 sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  to
 sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 sock.connect( (remotehost,port) )

 nbytes = sock.sendto(data, (remotehost,port))
  to
 nbytes = sock.send(data)

 Now, rerun your tests on your network. I expect you'll be faster now
 because TCP can be pretty smart about buffering. Let's say you write
 16, 90B blocks to the socket. If they are timely enough, it is
 possible all of those will be shipped across ethernet as a single
 frame. So what took 16 frames via UDP can now *potentially* be done in
 a single ethernet frame (assuming 1500MTU). I say potentially because
 the exact behaviour is OS/stack and NIC-driver specific and is often
 tunable to boot. Likewise, on the client end, what previously required
 15 calls to recvfrom, each returning 90B, can *potentially* be
 completed in a single call to recv, returning 1440B. Remember, fewer
 frames means less protocol overhead which makes more bandwidth
 available to your applications. When sending 90B datagrams, you're
 waisting over 48% of your available bandwidth because of protocol
 overhead (actually a lot more because I'm not accounting for UDP
 headers).

 Because of the differences between UDP and TCP, unlike your original
 UDP implementation which can receive from multiple clients, the TCP
 implementation can only receive from a single client. If you need to
 receive from multiple clients concurrently, look at python's select
 module to take up the slack.

 Hopefully you'll be up and running. Please report back your findings.
 I'm curious as to your results.

I've been out of online for a while. Anyway, clarifing few things:
- I am running on IO-bound
- we have 10/100/1000MB ethernet, and 10/100MB switches, routers,
servers,
- the MTU is default 1500

I know what you are saying regarding TCP. I was using it in another
project. However this project needs to be done using UDP and can't be
changed :(
Was testing today multiple approaches to client. Kept one similar to
the above one, rewrote one using threads and found another issue. The
speed is pretty acceptable, but there is an issue with sending
1.000.000 packets per client (it does it within around 1.5min). It
runs from a client machine to the server machine, both on the same
network. So, when sending milion packets only around 50%-70% are send
over. On the client machine it looks like all the packets where
transmitted however tcpdump running on the server shows that only
50-70% went through. I

Re: Getting in to metaprogramming

2008-11-25 Thread Aaron Brady

On Nov 25, 5:20 am, Michele Simionato [EMAIL PROTECTED]
wrote:
 On Nov 25, 12:12 pm, Rafe [EMAIL PROTECTED] wrote:

  is it really as simple as gathering strings of code?

 Yes.

Yes.

  Sort of like generating HTML or XML directly? Is there any other framework 
  or
  pattern set that is worth looking in to?

 Yes, the compiler module and the ast module in the standard library.
 You may also
 look at how templating languages that compile to Python code work (I
 mean mako
 or PTL/qpy). You may find interesting how the import hooks work too.

You could have Python generate HTML, Python generate COBOL, Python
generate Python, Perl generate Python, sure.  Not that I know COBOL.

If you're generating Python with Python, you only need one file to do
it, not two separate programs, as you would for the other
combinations; it was my point.  It could be really helpful or
unnecessary, depending on your application.

There are some templating modules, possibly for Python code.  If
anyone knows them, they can point them out.

I don't know a clean, reliable way to structure a metaprogram though.
Mine always turn out messy.
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converting a string data to a float value for access database

2008-11-25 Thread [EMAIL PROTECTED]

Hi,

I am trying to copy a sql database to a access database using python.
I can copy all the fields, but the date.  I can store a float value in
access data object, ie 
http://en.wikibooks.org/wiki/JET_Database/Data_types#Dates_and_times

So access uses a float for a date, and mysql databse uses text, I got
the following as the output 2008-11-25 09:59:39.
How can I convert the string 2008-11-25 09:59:39 from mysql to a float
for access??


-Ted
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Re: confused about classes and tkinter object design

On Nov 25, 2:31 pm, r [EMAIL PROTECTED] wrote:
 On Nov 25, 10:38 am, marc wyburn [EMAIL PROTECTED] wrote:



  Hi,

  I've created my first Tkinter GUI class which consists of some buttons
  that trigger functions.  I have also created a
  tkFileDialog.askdirectory control to local a root folder for log
  files.

  I have several file paths that depend on the value of
  tkFileDialog.askdirectory should I create an object that inherits this
  value or can I point functions at the GUI class?

  I am creating the tkinter GUI instance using;

  if __name__ == __main__:
      GUI = AuditorGUI()
      GUI.mainloop()

  class AuditorGUI(Frame):
      def __init__(self):
          Frame.__init__(self)
          self.pack(expand = YES, fill = BOTH)

  ##      Create GUI objects

          self.currentdir = StringVar()
          self.currentdir.set(os.getcwd())

          self.logdir = Button(self, text=Choose Data
  directory,command=self.choose_dir)
          self.logdir.grid(row=1,column=0,sticky='nsew',pady=20,padx=20)

          self.labeldirpath = Label(self, textvariable=self.currentdir)

      def choose_dir(self):
          dirname = tkFileDialog.askdirectory
  (parent=self,initialdir=self.currentdir.get(),title='Please select a
  directory')
          if len(dirname )  0:
              self.currentdir.set(dirname)

  I think I have created an instance of the AuditorGUI class called GUI
  so should be able to access the path using GUI.currentdir but this
  doesn't work.

  I'm still struggling with classes so not sure whether my problem is
  tkinter related or not.

  Thanks, MW

 first off i would use a different instance variable besides GUI.
 Could be AG or auditorgui.
 Also the conditional if len(dirname )  0: could simply be if
 dirname:
 When you ask for the attribute currentdir are you asking as
 GUI.currentdir.get() or GUI.currentdir???
 only the second will work with a TKVAR, but there is really no need to
 use a TKVAR here. I would simply do:

 self.currentdir = None

 then you could say:
 if GUI.currentdir:
     do this()

 When you ask for the attribute currentdir are you asking as
 GUI.currentdir.get() or GUI.currentdir???
 only the second will work with a TKVAR

correction:
only GUI.currentdir.get() will work with TKVAR
my bad:(
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Re: SWIG vs. ctypes (Was: ANN: PyEnchant 1.5.0)

2008-11-25 Thread rfk

 I'd be interested to hear about your
 experiences with both and why you switched.

Enchant has a pretty simple C API so the binding process was
straightforward with both SWIG and ctypes.  The only real trick was in
passing python functions as callbacks to the C API, for which I found
ctypes a little easier to use.

The switch wasn't motivated by any problems with SWIG, but simply
because ctypes seems to have a lot of momentum on the alternate python
implementations such as PyPy, Jython etc.

As others have noted, ctypes unfortunately doesn't support C++
bindings. There was a recent post on the PyPy blog discussing options
for C++ that you might be interested in:

   
http://morepypy.blogspot.com/2008/10/sprint-discussions-c-library-bindings.html


 Cheers,

   Ryan
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Re: Security implications of using open() on untrusted strings.

2008-11-25 Thread Jorgen Grahn

On Tue, 25 Nov 2008 20:40:57 +1300, Lawrence D'Oliveiro [EMAIL PROTECTED] 
wrote:
 Jorgen Grahn wrote:

 Seems to me you simply want to know beforehand that the reading will
 work.  But you can never check that!  You can stat(2) the file, or
 open-and-close it -- and then a microsecond later, someone deletes the
 file, or replaces it with another one, or write-protects it, or mounts
 a file system on top of its directory, or drops a nuke over the city,
 or ...


 Depends on what exactly you're trying to guard against. Your
 comments would apply, for example, to a set-uid program being run by a
 potentially hostile local user

Yeah, I know. I covered that in the part you snipped: Nor seems the
'user' input come from some other user than the one your program is
running as, nor from some input source which the user cannot be held
responsible for.

/Jorgen

-- 
  // Jorgen Grahn grahn@Ph'nglui mglw'nafh Cthulhu
\X/ snipabacken.se  R'lyeh wgah'nagl fhtagn!
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Re: end of print = lower productivity ?

2008-11-25 Thread Paul Rubin

[EMAIL PROTECTED] writes:
  BUT you now can do
   p = print
   p(f)

 All right. Let's talk about that.
 
 When I write print, it is both effortless and instantaneous : my
 hands do not move, a wave goes through my fingers, it all happens in a
 tenth of a second.
 
 Contrast this with what one has to go through to catch the SHIFT key ...

You could say:

class Printer:
def __isub__(self, x): print(x)
p = Printer()

Then

p-= foo

doesn't need use of the shift key.  Use of -= instead of - gets rid
of operator precedence issues.
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Re: converting a string data to a float value for access database

2008-11-25 Thread M.-A. Lemburg

On 2008-11-25 22:37, [EMAIL PROTECTED] wrote:
 Hi,
 
 I am trying to copy a sql database to a access database using python.
 I can copy all the fields, but the date.  I can store a float value in
 access data object, ie 
 http://en.wikibooks.org/wiki/JET_Database/Data_types#Dates_and_times
 
 So access uses a float for a date, and mysql databse uses text, I got
 the following as the output 2008-11-25 09:59:39.
 How can I convert the string 2008-11-25 09:59:39 from mysql to a float
 for access??

Use mxDateTime:

 from mx.DateTime import *
 DateTimeFrom('2008-11-25 09:59:39').COMDate()
39777.4164236

See http://www.egenix.com/products/python/mxBase/mxDateTime/

-- 
Marc-Andre Lemburg
eGenix.com

Professional Python Services directly from the Source  (#1, Nov 25 2008)
 Python/Zope Consulting and Support ...http://www.egenix.com/
 mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/
 mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/

2008-11-12: Released mxODBC.Connect 0.9.3  http://python.egenix.com/

 Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! 


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D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
   Registered at Amtsgericht Duesseldorf: HRB 46611
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Re: What are the syntax for , ||

2008-11-25 Thread Andrew Koenig


Peter Otten [EMAIL PROTECTED] wrote in message 
news:[EMAIL PROTECTED]

 How do I do in Python?

 if condition1 and condition2: # 
 doThis
 elif condition3 or condition4: # ||
 doThat

 See the pattern?

if condition1 and condition2:
doThis
elif condition3 or condition4:
doThat


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Re: Getting in to metaprogramming