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Re: Python presentations

References (3 earlier) <50525f48$0$6573$9b4e6d93@newsspool3.arcor-online.net> <mailman.646.1347575926.27098.python-list@python.org> <5053196e$0$6578$9b4e6d93@newsspool3.arcor-online.net> <mailman.699.1347625166.27098.python-list@python.org> <5055fab1$0$6579$9b4e6d93@newsspool3.arcor-online.net>
Date 2012-09-17 02:19 +1000
Subject Re: Python presentations
From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.804.1347812402.27098.python-list@python.org> (permalink)

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On Mon, Sep 17, 2012 at 2:13 AM, Alexander Blinne <news@blinne.net> wrote:
> def powerlist3(x,n):
>   return [x**i for i in xrange(n)]
>
> for really big n powerlist3 always takes very much time :)

I would reiterate that a really big n is a really unusual use case for
a function like this, except that... I frankly can't think of *any*
use case for it!! But for many many applications, the simplicity and
readability of a list comp instead of a function is usually going to
outweigh the performance differences.

However, it doesn't surprise me that individually raising a number to
successive powers is slower than iterative multiplication, assuming
you can't massively optimize eg with powers of 2 and bit shifts.

ChrisA

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Python presentations andrea crotti <andrea.crotti.0@gmail.com> - 2012-09-13 17:00 +0100
  Re: Python presentations John Gordon <gordon@panix.com> - 2012-09-13 16:06 +0000
  Re: Python presentations mblume <foobar@invalid.invalid> - 2012-09-13 16:26 +0000
    Re: Python presentations 88888 Dihedral <dihedral88888@googlemail.com> - 2012-09-13 12:01 -0700
      Re: Python presentations Alexander Blinne <news@blinne.net> - 2012-09-14 00:33 +0200
        Re: Python presentations Chris Angelico <rosuav@gmail.com> - 2012-09-14 08:38 +1000
          Re: Python presentations 88888 Dihedral <dihedral88888@googlemail.com> - 2012-09-13 22:57 -0700
          Re: Python presentations 88888 Dihedral <dihedral88888@googlemail.com> - 2012-09-13 22:57 -0700
          Re: Python presentations Alexander Blinne <news@blinne.net> - 2012-09-14 13:47 +0200
            Re: Python presentations Chris Angelico <rosuav@gmail.com> - 2012-09-14 22:19 +1000
              Re: Python presentations Alexander Blinne <news@blinne.net> - 2012-09-16 18:13 +0200
                Re: Python presentations Chris Angelico <rosuav@gmail.com> - 2012-09-17 02:19 +1000
                Re: Python presentations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-16 17:35 +0000
                Re: Python presentations Alexander Blinne <news@blinne.net> - 2012-09-17 10:39 +0200
  Re: Python presentations Miki Tebeka <miki.tebeka@gmail.com> - 2012-09-13 15:58 -0700
    Re: Python presentations Andrea Crotti <andrea.crotti.0@gmail.com> - 2012-09-14 00:15 +0100
  Re: Python presentations Miki Tebeka <miki.tebeka@gmail.com> - 2012-09-13 15:58 -0700

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