On Sun, Apr 26, 2020 at 4:42 AM Stephen J. Turnbull <
turnbull.stephen...@u.tsukuba.ac.jp> wrote:
> You're missing the topic of the comparison. It is that we could have
>
> removeaffix(source, affix, suffix=True)
> strip(self, chars, where='both') # where in {both, left, right}
>
Oh, that's not the point I was making, but it is also good.
During the .removeprefix() discussion, several people seriously suggested
something like `mystring.lstrip('foo', string=True)` to alter the behavior
between removing from a set of characters and removing a specific
subsequence. In any case, that was not what won out, which was my point.
I agree that a `where=left|right|both` would be the wrong design for
similar reasons.
> I'm not sure why David compares this to the case of print(), where end
> and sep are arbitrary strings.
Yeah, OK, that is weaker. I guess I was just thinking of the fact that my
sep is almost always either the default space or the empty string. And my
end is similarly almost always either newline or space. But of course I
*could* use anything else (and occasionally do).
Ditto open(), where the mode argument
> is not 2-valued, but (text, binary) X (read, write, append,
> create_no_truncate) X (update, not) X (universal newline, not). Not
> only that, but there are other 'mode' arguments such as encoding,
> errors, and closefd.
>
Oh... I'll stick with the open() example. Even though the mode is this
compound string, it's really conceptually separate elements (and the
documentation makes this point). Text|Binary is a two-value switch, even
though it is encoded as a character of a potentially multi-character
string. That slightly cryptic string code is legacy IMO (but it's not
going to change). Likewise, `newline` is an actual separate argument that
takes a small number of options.
> The convention is that rather than a function foo(..., mode) where
> mode takes values from a "very small" enum, say {bar, baz, default},
> it's preferable to have foo, foo_bar, and foo_baz. I'd guess #enum=4
> (including default) is about the limit, which is why open has all
> those enumerated mode arguments: even errors has more than 4 options.
>
Yeah, I agree. Even if the individual aspects of mode are each few enough
that separate functions would make sense, the cross product of their
combinations becomes large, and we wouldn't want separate functions even if
we were starting today.
--
Keeping medicines from the bloodstreams of the sick; food
from the bellies of the hungry; books from the hands of the
uneducated; technology from the underdeveloped; and putting
advocates of freedom in prisons. Intellectual property is
to the 21st century what the slave trade was to the 16th.
_______________________________________________
Python-ideas mailing list -- python-ideas@python.org
To unsubscribe send an email to python-ideas-le...@python.org
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at
https://mail.python.org/archives/list/python-ideas@python.org/message/VO27YQI2AS3Q2XGCBDTQCIQVN7WBQ4CM/
Code of Conduct: http://python.org/psf/codeofconduct/
