[Python-ideas] More user-friendly version for string.translate()

[Mikhail V]

On 24 October 2016 at 23:10, Paul Moore <p.f.moore at gmail.com> wrote:
> On 24 October 2016 at 21:54, Chris Barker <chris.barker at noaa.gov> wrote:
>> I don't know a way to do "remove every character except these", but someone
>> I expect there is a way to do that efficiently with Python strings.
>
> It's easy enough with the re module:
>
>>>> re.sub('[^0-9]', '', 'ab0c2m3g5')
> '0235'
>
> Possibly because there's a lot of good Python builtins that allow you
> to avoid the re module when *not* needed, it's easy to forget it in
> the cases where it does pretty much exactly what you want, or can be
> persuaded to do so with much less difficulty than rolling your own
> solution (I know I'm guilty of that...).
>
> Paul

Thanks, this would solve the task of course.
However for example in the case in my last example (filenames)
this would require:

- Write a function to construct the expression for "all except given"
characters from my table. This could be easy I believe, but still another task.

Then:
1. Apply translate() with my table to the string.
2. Apply re.sub() to the string.

I usually start using RE when I want to find/replace words or patterns,
but not translate/filter the characters directly. So since there is
already an "inclusive"
translate() then probably having an "exclusive" one is not a bad idea.
I believe it is something very similar in implementation, so instead
of appending next character which is not in the table, it simply does nothing.

Mikhail