[Python-Dev] string.find() again (was Re: timsort for jython)

[Tim Peters]

[Tim]
> I'd like to see a plausible use case for
>
>     '' in str
>
> returning True, then.

[Gordon McMillan]
> Any code that currently does
>  str.find(x) >= 0

You're saying that you actually do that in cases where x may be an empty
string, and that it's useful to get a True result in at least one such case?
If you are saying that, it needs more details; but if you're not saying
that, it's not a relevant use case.

> I tend to use:
>
>  pos = str.find(x)
>  if pos > -1:
>
> because I'm normally interested in where.

Sure -- that's what .find() is for, after all.  But you're also saying that
your algorithms expect to search for empty strings?  Like in:

    index = option_letter_string.find(letter)
    if index >= 0:
        list_of_option_functions[index]()
    else:
        raise UnknownOptionLetter(letter)

you make sure that list_of_option_functions[0] is suitable for processing
both the first option in option_letter_string and an empty "option letter"?