[Python-ideas] Fast sum() for non-numbers

[Ron Adam]

On 07/03/2013 07:43 AM, Steven D'Aprano wrote:
>
> I'm not sure that sum() is the Obvious Way to concatenate lists, and I
> don't think that concatenating many lists is a common thing to do.
> Traditionally, sum() works only on numbers, and I think we wouldn't be
> having this discussion if Python used & for concatenation instead of +. So
> I don't care that sum() has quadratic performance on lists (and tuples),
> and I must admit that having a simple quadratic algorithm in the built-ins
> is sometimes useful for teaching purposes, so I'm -0 on optimizing this case.

I agree, and wished sequences used a __join__ method instead of __add__.


The '&' is already used for Bitwise And.  How about '++' instead?


     'hello ' ++ 'world' == "hello world"

     [1, 3, 3] ++ [4, 5, 6] == [1, 2, 3, 4, 5, 6]


While this doesn't seem like a big change, I think it would simplify code 
in many places that is more complicated than it really needs to be.

Cheers,
    Ron