On 2019-03-31 17:17, David Mertz wrote:
On Sun, Mar 31, 2019 at 12:09 PM MRAB <pyt...@mrabarnett.plus.com
<mailto:pyt...@mrabarnett.plus.com>> wrote:
> That said, I really like Brandt's ideas of expanding the
signature of
> .lstrip/.rstrip instead.
>
> mystring.rstrip("abcd") # remove any of these single character
suffixes
It removes _all_ of the single character suffixes.
> mystring.rstrip(('foo', 'bar', 'baz')) # remove any of these
suffixes
In keeping with the current behaviour, it would strip _all_ of these
suffixes.
Yes, the exact behavior would need to be documented. The existing
case indeed removes *ALL* of the single letter suffixes. Clearly that
behavior cannot be changed (nor would I want to, that behavior is useful).
It's a decision about whether passing a tuple of substrings would
remove all of them (perhaps repeatedly) or only one of them. And if
only one, is it "longest wins" or "first wins." As I say, any choice
of the semantics would be fine with me if it were documented... since
this edge case will be uncommon in most uses (certainly in almost all
of my uses).
E.g.
basename = fname.rstrip(('.jpg', '.png', 'gif'))
This is rarely ambiguous, and does something concretely useful that
I've coded many times. But what if:
fname = 'silly.jpg.png.gif.png.jpg.gif.jpg'
I'm honestly not sure what behavior would be useful most often for
this oddball case. For the suffixes, I think "remove them all" is
probably the best; that is consistent with thinking of the string
passed in the existing signature of .rstrip() as an iterable of
characters.
But even if the decision was made to "only remove the single thing at
end", I'd still find the enhancement useful. Sure, once in a while
someone might trip over the choice of semantics in this edge case, but
if it were documented, no big deal.
Could/should we borrow from .replace, which accepts a replace count?
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