[Python-ideas] Vectorization [was Re: Add list.join() please]

[Chris Angelico]

On Sun, Feb 3, 2019 at 10:36 AM Ben Rudiak-Gould <benrudiak at gmail.com> wrote:
>
> On Sat, Feb 2, 2019 at 3:23 PM Christopher Barker <pythonchb at gmail.com> wrote:
>>
>> a_list_of_strings.strip().lower().title()
>>
>> is a lot nicer than:
>>
>> [s.title() for s in (s.lower() for s in [s.strip(s) for s in a_list_of_strings])]
>>
>> or
>>
>> list(map(str.title, (map(str.lower, (map(str.strip, a_list_of_strings)))) # untested
>
> In this case you can write
>
>     [s.strip().lower().title() for s in a_list_of_strings]

What if it's a more complicated example?

len(sorted(a_list_of_strings.casefold())[:100])

where the len() is supposed to give back a list of the lengths of the
first hundred strings, sorted case insensitively? (Okay so it's a
horrible contrived example. Bear with me.)

With current syntax, this would need multiple map calls or comprehensions:

[len(s) for s in sorted(s.casefold() for s in a_list_of_strings)[:100]]

(Better examples welcomed.)

ChrisA