Python .rstrip() strips a string even if it doesn't match exactly

Question

print('345nov'.rstrip('nov'))

the code above prints what you would expect: 345

So why does print('345v'.rstrip('nov')) print the same thing. The string doesn't end with "nov". It only ends with "v". But rstrip() strips it all the same. Either way, how can I make it ignore this behavior and not strip anything unless the ending string matches it exactly.

Note that this behavior is mentioned in the [docs](https://docs.python.org/3/library/stdtypes.html#str.rstrip). — 0x5453, Mar 17 '20 at 20:58
A dedicated method for that purpose doesn't exist (yet) but there's a discussion on [python-ideas](https://mail.python.org/archives/list/python-ideas@python.org/thread/RJARZSUKCXRJIP42Z2YBBAEN5XA7KEC3/) whether to add one. — a_guest, Mar 17 '20 at 20:59
Conceptually a duplicate of [the same question on `lstrip`](https://stackoverflow.com/questions/58840638/why-i-am-getting-these-different-outputs). — Jongware, Mar 17 '20 at 21:02

score 2 · Answer 1 · answered Mar 17 '20 at 20:58

You get this behavior because rstrip() actually takes an iterable for its parameter. That means the string you place in ("nov") is interpreted as ['n', 'o', 'v']. This can be proved further by changing the order of the characters:

>>>"345nov".rstrip("nvo")
345

score 1 · Answer 2 · answered Mar 17 '20 at 20:55

1

You can use endswith and index the string:

string = '345v'
suffix = 'nov'
if string.endswith(suffix):
    string = string[:-len(suffix)]

answered Mar 17 '20 at 20:55

a_guest

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Directory · Answer 3 · 2020-03-17T21:02:08.023

0

I ended up doing something similar to @a_guest.

def rstrip(a, b):
    if a.endswith(b):
        return a[:-len(b)]
    return a

edited Mar 17 '20 at 21:02

answered Mar 17 '20 at 20:59

Python .rstrip() strips a string even if it doesn't match exactly

3 Answers3