[Python-ideas] Length hinting and preallocation for container types

Daniel Holth dholth at gmail.com
Fri Mar 8 15:55:59 CET 2013

On Fri, Mar 8, 2013 at 9:48 AM, Stefan Behnel <stefan_ml at behnel.de> wrote:
> Eli Bendersky, 08.03.2013 15:40:
>> On Fri, Mar 8, 2013 at 6:04 AM, Daniel Holth wrote:
>>> On Fri, Mar 8, 2013 at 8:35 AM, Antoine Pitrou wrote:
>>>> Le Fri, 8 Mar 2013 08:18:07 -0500,
>>>> Daniel Holth a écrit :
>>>>> I am a fan of the proposal. Imagine you are programming for a
>>>>> memory-constrained system. By telling the list how big it needs to be
>>>>> you can save precious RAM.
>>>> Is it an actual use case or are you just imagining it? :)
>>>> I'm asking because, unless you are only allocating that list and all
>>>> the objects contained it in it already exist, limiting the list's size
>>>> won't do much for the process' memory occupation.
>>> It might help if it was a list of integers between -1 and 99 and
>>> 1-character strings.
>> That's not what you should use lists for if memory consumption matters. Use
>> http://docs.python.org/dev/library/array.html, especially if your integers
>> are in such a limited range.
> Yep, and regarding the second part, a string is a very efficient way to
> store many 1-character strings.
> Stefan

I do know C

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