Re: Python's garbage collection was Re: Python reliability

[Patrick Down]

Paul Rubin wrote:

> I haven't been keeping up with this stuff in recent years so I have a
> worse concern.  I don't know whether it's founded or not.  Basically
> in the past decade or so, memory has gotten 100x larger and cpu's have
> gotten 100x faster, but memory is less than 10x faster once you're out
> of the cpu cache.  The mark phase of mark/sweep tends to have a very
> random access pattern (at least for Lisp).  In the old days that
> wasn't so bad, since a random memory access took maybe a couple of cpu
> cycles, but today it takes hundreds of cycles.  So for applications
> that use a lot of memory, simple mark/sweep may be a much worse dog
> than it was in the Vax era, even if you don't mind the pauses.

You pay a price for CG one way or the other.  In Python the price is
spread out among a bunch of increment and decrement operations in the
code.  For mark and sweep the price is a big operation done less often.
 My understanding from reading about GC implementations is that
reference counting can exhibit poor cache performance because
decrementing a reference can lead to a chain of decrements on objects
that can be laid out in memory in a fairly random fashion.  Mark and
sweep can be a better cache performer since it's memory access will
tend to be more linear.

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Re: newbie question concerning formatted output

[Patrick Down]

>>> a = [str(i) for i in range(0,17)]
>>> for i in range(0,len(a),3):
... print " ".join(a[i:i+3])
...
0 1 2
3 4 5
6 7 8
9 10 11
12 13 14
15 16

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Re: Moinmoin config

[Patrick Down]

Mark wrote:
> Hi,
>
> I have Moinmoin 1.3.4 installed and working on Linux RHEL3.0.  However,
> all screen elements are lined up on the left hand side.   How can I get
> it displayed like the wiki at:

Well, this is probably a better question for the moin lists but
I have seen this behavior before.  I would check the

data_underlay_dir = './underlay/'

line in your wikiconfig.py file.  If it's not getting the right
templates it won't format the page right.   This is the only
advice I can give.  Beyond this I don't know what else you can
try.

>
> http://moinmoin.wikiwikiweb.de/HelpOnConfiguration
>
> instead of this ? ->
>
> LANShieldOS Release Notes
> Search:
>
> * MarkRuedy
> * UserPreferences
>
> * HelpOnEditing
> * HelpContents
> * HelpForBeginners
> * UserPreferences
>
> * FrontPage
> * RecentChanges
> * FindPage
> * HelpContents
>
> * Edit
> * Show Changes
> * Get Info
> * Subscribe
> *
> 
> FrontPage

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Re: What is proper way to require a method to be overridden?

[Patrick Down]

jeremito wrote:
> I am writing a class that is intended to be subclassed.  What is the
> proper way to indicate that a sub class must override a method?
>
> Thanks,
> Jeremy

Decorators to the rescue?

def must_override(f):
def t(*args):
raise NotImplementedError("You must override " + f.__name__)
return t

class Foo:
@must_override
def Bar(x,y): pass

Foo().Bar()

Traceback (most recent call last):
  File "testit.py", line 14, in ?
Foo().Bar()
  File "testit.py", line 5, in t
raise NotImplementedError("You must override " + f.__name__)
NotImplementedError: You must override Bar

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Re: If - Or statements

[Patrick Down]

What about:

if True in [thefile.endswith(x) for x in
('mp3','mp4','ogg','aac','wma')]:

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Re: Python in Games (was RE: [Stackless] Python in Games)

[Patrick Down]

My understanding is that the upcoming Civilization IV will have python
scripting.

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Re: if __name__ == 'main':

[Patrick Down]

On Mar 20, 11:49 am, "gtb" <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I often see the following 'if' construct in python code. What does
> this idiom accomplish? What happens if this is not main? How did I get
> here if it is not main?

A quick example demonstrates the usage:

C:\code>type temp.py


print "Module name is",__name__

if __name__ == "__main__":
print "I was not imported"
else:
print "I was imported"

C:\code>python temp.py
Module name is __main__
I was not imported

C:\code>python
Python 2.4.3 (#69, Mar 29 2006, 17:35:34) [MSC v.1310 32 bit (Intel)]
on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import temp
Module name is temp
I was imported


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