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Re: First attempt at a Python prog (Chess)

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On Thu, Feb 14, 2013 at 10:48 AM, Chris Hinsley <chris.hinsley@gmail.com> wrote:
> Is a Python list as fast as a bytearray ? I didn't copy a C prog BTW !

>>> from timeit import Timer
>>> t1 = Timer("board[36] = board[20]; board[20] = ' '", "board = bytearray('RNBQKBNRPPPPPPPP                                pppppppprnbqkbnr')")
>>> min(t1.repeat(10))
0.1678651895701826
>>> t2 = Timer("board[3][4] = board[1][4]; board[1][4] = ' '", "board = [list('RNBQKBNR'), ['P'] * 8] + [[' ']*8 for i in range(4)] + [['p'] * 8, list('rnbqkbnr')]")
>>> min(t2.repeat(10))
0.2080088391122672

Natively, it looks like the bytearray is about 19% faster for moving a
piece from one square to another.  Those array offsets aren't
calculated for free, though.  Look what happens when we have to do the
math:

>>> t3 = Timer("board[r1*8+c1] = board[r2*8+c2]; board[r2*8+c2] = ' '", "board = bytearray('RNBQKBNRPPPPPPPP                                pppppppprnbqkbnr'); r1 = 3; r2 = 1; c1 = c2 = 4")
>>> min(t3.repeat(10))
0.314191887516472
>>> t4 = Timer("board[r1][c1] = board[r2][c2]; board[r2][c2] = ' '", "board = [list('RNBQKBNR'), ['P'] * 8] + [[' ']*8 for i in range(4)] + [['p'] * 8, list('rnbqkbnr')]; r1 = 3; r2 = 1; c1 = c2 = 4")
>>> min(t4.repeat(10))
0.24427881197186707

That said, the philosophy of Python focuses more on readability than
on speed.  The goalpost for speed in a Python program is that it be
"fast enough".  If you have more stringent speed requirements than
that, then Python may not be the right tool for the job.

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First attempt at a Python prog (Chess) Chris Hinsley <chris.hinsley@gmail.com> - 2013-02-13 23:25 +0000
  Re: First attempt at a Python prog (Chess) Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-13 23:55 +0000
    Re: First attempt at a Python prog (Chess) Chris Hinsley <chris.hinsley@gmail.com> - 2013-02-14 01:31 +0000
  Re: First attempt at a Python prog (Chess) Tim Roberts <timr@probo.com> - 2013-02-13 22:05 -0800
    Re: First attempt at a Python prog (Chess) Chris Hinsley <chris.hinsley@gmail.com> - 2013-02-14 17:48 +0000
      Re: First attempt at a Python prog (Chess) Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-14 11:30 -0700
      Re: First attempt at a Python prog (Chess) Tim Roberts <timr@probo.com> - 2013-02-18 20:15 -0800
        Re: First attempt at a Python prog (Chess) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-19 06:24 +0000
        Re: First attempt at a Python prog (Chess) Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-19 12:41 -0700
  Re: First attempt at a Python prog (Chess) jkn <jkn_gg@nicorp.f9.co.uk> - 2013-02-14 13:14 -0800
    Re: First attempt at a Python prog (Chess) Chris Hinsley <chris.hinsley@gmail.com> - 2013-02-14 22:13 +0000
      Re: First attempt at a Python prog (Chess) Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-14 22:09 -0500
  Re: First attempt at a Python prog (Chess) Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-14 21:05 -0800
  Re: First attempt at a Python prog (Chess) Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-15 11:22 +0000
    Re: First attempt at a Python prog (Chess) Neil Cerutti <neilc@norwich.edu> - 2013-02-15 16:17 +0000
      Re: First attempt at a Python prog (Chess) MRAB <python@mrabarnett.plus.com> - 2013-02-15 17:52 +0000
        Re: First attempt at a Python prog (Chess) Neil Cerutti <neilc@norwich.edu> - 2013-02-19 21:10 +0000
      Re: First attempt at a Python prog (Chess) Matt Jones <matt.walker.jones@gmail.com> - 2013-02-15 12:03 -0600
  Re: First attempt at a Python prog (Chess) Tim Golden <mail@timgolden.me.uk> - 2013-02-15 11:36 +0000
  Re: First attempt at a Python prog (Chess) Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-15 13:11 +0000
  Re: First attempt at a Python prog (Chess) Tim Golden <mail@timgolden.me.uk> - 2013-02-15 15:36 +0000
    Re: First attempt at a Python prog (Chess) Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-02-15 18:48 +0200
  Re: First attempt at a Python prog (Chess) Chris Angelico <rosuav@gmail.com> - 2013-02-16 02:49 +1100
  Re: First attempt at a Python prog (Chess) Tim Golden <mail@timgolden.me.uk> - 2013-02-15 17:37 +0000
  Re: First attempt at a Python prog (Chess) Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-15 13:41 -0500
  Re: First attempt at a Python prog (Chess) Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-16 14:39 +0000

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