[Python-ideas] Add "equal" builtin function

[Mark Lawrence]

On 06/10/2016 15:43, Sjoerd Job Postmus wrote:
> On Thu, Oct 06, 2016 at 03:01:36PM +0100, Paul Moore wrote:
>> On 6 October 2016 at 14:45, Filipp Bakanov <filipp at bakanov.su> wrote:
>>> For now there are many usefull builtin functions like "any", "all", etc. I'd
>>> like to propose a new builtin function "equal". It should accept iterable,
>>> and return True if all items in iterable are the same or iterable is emty.
>>> That's quite popular problem, there is a discussion of how to perform it on
>>> stackoverflow
>>> (http://stackoverflow.com/questions/3844801/check-if-all-elements-in-a-list-are-identical)
>>> - all suggestions are either slow or not very elegant.
>>> What do you think about it?
>>
>> It's not a problem I've needed to solve often, if at all (in
>> real-world code). But even if we assume it is worth having as a
>> builtin, what would you propose as the implementation? The
>> stackoverflow discussion highlights a lot of approaches, all with
>> their own trade-offs. One problem with a builtin is that it would have
>> to work on all iterables, which is likely to preclude a number of the
>> faster solutions (which rely on the argument being an actual list).
>>
>> It's an interesting optimisation problem, and the discussion gives
>> some great insight into how to micro-optimise an operation like this,
>> but I'd question whether it needs to be a language/stdlib feature.
>>
>> Paul
>
> I've needed it several times, but can't really remember what for
> anymore, which makes me think it's not really that important.
> A motivating reason for adding it to the builtins would be that it can
> be written in C instead of Python, and hence be a lot faster.

This should be on the bug tracker as "release blocker" as we clearly 
need something that is fast that isn't that important.

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence