[Python-Dev] str.lstrip bug?

[Isaac Schwabacher]

On 15-03-10, Facundo Batista  wrote:
> On Tue, Mar 10, 2015 at 2:27 PM, lou xiao <lox.xiao at gmail.com> wrote:
> 
> > tiny➜ ~ python
> > Python 2.7.5+ (default, Feb 27 2014, 19:37:08)
> > [GCC 4.8.1] on linux2
> > Type "help", "copyright", "credits" or "license" for more information.
> >>>> a='device_info'
> >>>> a.lstrip('device')
> > '_info'
> >>>> a.lstrip('device_')
> > 'nfo'
> 
> On one hand, this is the "development of python itself" list; this
> issue was more aimed to the general python list, of you was sure that
> this is a real bug, to the issue tracker.
> 
> On the other hand, this is not a bug! If you pass a parameter to
> lstrip it will (quoted from its help) "remove characters in chars
> instead.", so the moment you pass "device_", it removes all those
> characers from the left... note that the 'i' is removed twice.

That said, I bet this is the most common string-munging operations that *isn't* available as a single function in the stdlib. I know my bash code is full of ${filename%.suffix} and such, and the fact that in python I have to either import re or resort to some combination of (starts|ends)with, r?partition, slicing and an if-clause makes that sort of code much more verbose and harder to read. Pathlib's Path.with_suffix helps in some but not all of these cases. Maybe the stdlib should have a simple way to do this? It could even be added as a kwarg (exact=False) to str.[lr]strip to minimize the effect on the API; alternatively it could be str.strip(prefix|suffix).

ijs

> Regards,
> 
> -- 
> . Facundo
> 
> Blog: http://www.taniquetil.com.ar/plog/
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