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Groups > comp.lang.python > #61706

Re: Optimizing list processing

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On 12/12/2013 12:25, Chris Angelico wrote:
> On Thu, Dec 12, 2013 at 11:08 PM, Steven D'Aprano
> <steve+comp.lang.python@pearwood.info> wrote:
>> P.S. The algorithm I'm working on is a way of generating index and rank
>> tables. Not that it really matters -- what matters is determining whether
>> or not to shift from "make a copy of the list" to "modify the list in
>> place".
>
> So you're currently looking at...
>
> if len(table) < ?????:
>      table = [i for x,i in table]
> else:
>      for x, i in table:
>          table[i] = x
>
>
> Can I throw a spanner [1] in the works with other suggestions to try timing?
>
> table[:] = [i for x,i in table]  # Does slice assignment get optimized?
>
[snip]

If you're trying that, you could also try:

table[:] = (i for x,i in table)

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Optimizing list processing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-11 23:54 +0000
  Re: Optimizing list processing MRAB <python@mrabarnett.plus.com> - 2013-12-12 00:59 +0000
    Re: Optimizing list processing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-12 01:43 +0000
      Re: Optimizing list processing MRAB <python@mrabarnett.plus.com> - 2013-12-12 02:09 +0000
  Re: Optimizing list processing duncan smith <buzzard@invalid.invalid> - 2013-12-12 01:02 +0000
  Re: Optimizing list processing Ben Finney <ben+python@benfinney.id.au> - 2013-12-12 12:18 +1100
  Re: Optimizing list processing Terry Reedy <tjreedy@udel.edu> - 2013-12-11 21:26 -0500
    Re: Optimizing list processing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-12 12:08 +0000
      Re: Optimizing list processing Chris Angelico <rosuav@gmail.com> - 2013-12-12 23:25 +1100
      Re: Optimizing list processing MRAB <python@mrabarnett.plus.com> - 2013-12-12 13:32 +0000
      Re: Optimizing list processing Chris Angelico <rosuav@gmail.com> - 2013-12-13 01:06 +1100
      Re: Optimizing list processing Terry Reedy <tjreedy@udel.edu> - 2013-12-12 13:40 -0500
        Re: Optimizing list processing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-13 00:14 +0000
          Re: Optimizing list processing Chris Angelico <rosuav@gmail.com> - 2013-12-13 12:01 +1100
  Re: Optimizing list processing Stefan Behnel <stefan_ml@behnel.de> - 2013-12-12 12:09 +0100
  Re: Optimizing list processing Peter Otten <__peter__@web.de> - 2013-12-12 16:08 +0100
    Re: Optimizing list processing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-13 03:01 +0000
      Re: Optimizing list processing rusi <rustompmody@gmail.com> - 2013-12-12 21:35 -0800
  Re: Optimizing list processing Terry Reedy <tjreedy@udel.edu> - 2013-12-12 13:07 -0500

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