Re: [pygame] Does anyone have a python implementation of A*?

[Magnus Lie Hetland <magnus@hetland.org>]

John Eikenberry <jae@zhar.net>:
>
> Hmm... I didn't make many other changes besides what was needed to
> change to comprehensions. I'll mess around more to test what is actually
> responsible.
 
How did you build the list before changing to list comprehensions? In
my example I preallocated a list of the correct length, which will
give you roughly the same performance as a list comprehension. (The
plain for loop seems a tad faster -- I'm not sure exactly why.) Using
append() or += will give you slightly lower performance (with += being
slower than append) but nothing drastic. About a factor 2 for +=. If,
however, you do something that creates a lot of lists, such as

  thelist = thelist + [newitem]

then things will start going really wrong. My tests indicate an
slowdown factor of about 100, as you reported in your program.

> Just to be sure we're all on the same page, I'm using python 2.1.2.

2.2 here.

--
Magnus Lie Hetland                                  The Anygui Project
http://hetland.org                                  http://anygui.org
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