On Tue, Jul 2, 2019 at 4:24 PM <brian.sk...@gmail.com> wrote:
> It seems to me that the desired behavior here is closest to
> 'str.replace()' out of all the options discussed, just with the constraint
> of being limited to either the start or the end of the string. (Thus the
> .lreplace() and .rreplace() option suggested by Glenn.)
>
> The minimal change (which actually also is pretty general?) I think would
> be to add 'only_start' and 'only_end' keyword arguments to str.replace(),
> both defaulting to False. If, e.g., 'only_start' is passed True, each
> repetition of 'old' at the start of 's' is replaced by 'new', with the
> number of replacements limited by the existing optional 'count'. Similar
> behavior for 'only_end'=True. Probably best to raise a ValueError(?) if
> both 'only_start'=True and 'only_end'=True?
>
> Taking swapping a file extension as an example of a particular
> transformation of interest, it would be achieved with something like
> s.replace(".htm", ".html", only_end=True).
>
> -Brian
Just to add my own touch of colour to the bike shed, I'd suggest that more
naturally-usable names for those arguments, should they be added, would be
at_start and at_end.
regards
Steve
_______________________________________________
Python-Dev mailing list -- python-dev@python.org
To unsubscribe send an email to python-dev-le...@python.org
https://mail.python.org/mailman3/lists/python-dev.python.org/
Message archived at
https://mail.python.org/archives/list/python-dev@python.org/message/IVIUHDKO7WWORNFNUQDGDVVH2LYUKLXI/
