[Python-ideas] The non-obvious nature of str.join (was Re: sum(...) limitation)

[Ethan Furman]

On 08/11/2014 02:53 PM, Nathaniel Smith wrote:
>>
>> Quite frankly, I regard this as a point in sum's favor.  We have, effectively, a string-subclass and join chokes on it.
>
> Yes, but the proposal I was responding to was to do something like
>
> def sum(it, start=0):
>      if start == "":
>          return "".join(it)
>      ... regular sum impl here ...
>
> And the point is that this is not trivially a transparent optimization.

Ah, gotcha.

Even without an optimization in sum, I'd still rather it did what it said:  add things together.

--
~Ethan~