On Tue, May 02, 2017 at 09:07:41PM -0400, Juancarlo Añez wrote:
> On Tue, May 2, 2017 at 8:43 PM, Steven D'Aprano <st...@pearwood.info> wrote:
>
> > String methods should return strings.
> >
>
> >>> "A-B-C".split("-")
> ['A', 'B', 'C']
Yes, thank you. And don't forget:
py> 'abcd'.index('c')
2
But in context, I was responding to the question of why this proposed
chunk()/group() method returns a string rather than an iterator. I
worded my answer badly, but the intention was clear, at least in my own
head *wink*
Given that we were discussing a method that both groups the characters
of a string and inserts the separators, it makes sense to return a
string, like other string methods:
'foo'.upper() returns 'FOO', not iter(['F', 'O', 'O'])
'cheese and green eggs'.replace('green', 'red') returns a string,
not iter(['cheese and ', 'red', ' eggs'])
'xyz'.zfill(5) returns '00xyz' not iter(['00', 'xyz'])
etc, and likewise:
'abcdef'.chunk(2, sep='-') should return 'ab-cd-ef' rather than
iter(['ab', '-', 'cd', '-', 'ef'])
If we're talking about a different API, one where only the grouping is
done and inserting separators is left for join(), then my answer will be
different. In that case, then it is a matter of taste whether to return
a list (like split()) or an iterator. I lean slightly towards returning
a list, but I can see arguments for and against both.
--
Steve
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