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

Stefan Behnel stefan_ml at behnel.de
Fri Mar 8 16:02:01 CET 2013

Daniel Holth, 08.03.2013 15:55:
> On Fri, Mar 8, 2013 at 9:48 AM, Stefan Behnel 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.
> I do know C

So do I. This thread is about Python, though. At least, that's what I think
it is.


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