Python : go backwards through a string, then remove everything after a specific character

Question

I have a string, which after a character I wish to remove everything after the character. However, the issue is that I have multiple characters like this in the string and its only the characters after the last one which I wish to remove.

for example:

str = "howdie how are you? are you good? sdfsdf"
str = str.RemoveEverythingAfterLast("?")
str = "howdie how are you? are you good?"

I was wondering if there was an efficient way to do this in python? I had thought of looping backwards through the string deleting characters 1 by 1 until I found the character I was looking for (in example the '?'). But I was wondering if there was a more efficient way to go about this?

by using `str` as name, you are overwriting built-in function, you should avoid that and use other name — m.wasowski, Mar 19 '14 at 22:37

Martijn Pieters · Accepted Answer · 2014-03-19T22:22:36.340

7

Use str.rpartition():

''.join(string.rpartition('?')[:2])

Demo:

>>> string = "howdie how are you? are you good? sdfsdf"
>>> ''.join(string.rpartition('?')[:2])
'howdie how are you? are you good?'

edited Mar 19 '14 at 22:22

answered Mar 19 '14 at 22:16

Martijn Pieters

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Looks from question like OP wants the question mark left on the output, btw. – Two-Bit Alchemist Mar 19 '14 at 22:18
@Two-BitAlchemist: ah, adjusted. – Martijn Pieters Mar 19 '14 at 22:22
returns empty string if separator is not in input string – m.wasowski Mar 19 '14 at 22:28
@m.wasowski: which is easy enough to test for, of course. – Martijn Pieters Mar 19 '14 at 22:30
@MartijnPieters of course, or add `x if cond else y` expression inside join ;o) – m.wasowski Mar 19 '14 at 22:36

score 1 · Answer 2 · answered Mar 19 '14 at 22:17

1

Using regex:

str = re.sub("(.*\?).*", "\\1", str)

capturing the group till the last ? and replace it with captured group \\1.

answered Mar 19 '14 at 22:17

Sabuj Hassan

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score 1 · Answer 3 · edited May 23 '17 at 12:11

1

You can use str.rfind and slicing:

>>> string = "howdie how are you? are you good? sdfsdf"
>>> string[:string.rfind("?") + 1]
'howdie how are you? are you good?'
>>>

The + 1 will cause the ? to be left on the end of the returned string.

edited May 23 '17 at 12:11

Community

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answered Mar 19 '14 at 22:21

Great, didn't know about `rfind`. That simplifies a lot what I tried to do :) – Paulo Bu Mar 19 '14 at 22:23

Python : go backwards through a string, then remove everything after a specific character

3 Answers3