string.rstrip

[Peter Otten]

Hank wrote:

> Hi,
> 
> I have this problem with string.rstrip
> 
> Python 2.2.3 (#42, May 30 2003, 18:12:08) [MSC 32 bit (Intel)] on
> win32
> Type "help", "copyright", "credits" or "license" for more information.
>>>> import string
>>>> mystr = "test.txt"
>>>> mystr = string.rstrip(mystr, ".txt")
>>>> print mystr
> tes
> 
> The last 't' was stripped. Is this fixed or documented anywhere? it
> works for other cases, but this one seems to give me a weird result.

There are several issues with your code. The preferred way to invoke
rstrip() is now as a method, so

>>> mystr = "test.txt"
>>> mystr.rstrip(".txt")
'tes'

Why's that? Think of the argument of rstrip() as a character set rather than
a string; characters are removed from the end of mystr as long as they are
in [".", "t", "x"].

To remove an arbitrary suffix you can write your own function:

>>> def removeSuffix(s, suffix):
...     if s.endswith(suffix):
...             return s[:-len(suffix)]
...     return s
...
>>> removeSuffix(mystr, ".txt")
'test'

However, I guess that what you really want is to remove the filename
extension:

>>> import os
>>> os.path.splitext(mystr)
('test', '.txt')

>>> os.path.splitext(mystr)[0]
'test'

This returns both parts of the string and thus gives you the chance to check
if the extension is really what you expected.

One caveat: only the last extension is cut off the filename.

>>> os.path.splitext("test.tar.gz")
('test.tar', '.gz')


Peter