Python: Strip everything but spaces and alphanumeric

Question

I have a large string with brackets and commas and such. I want to strip all those characters but keep the spacing. How can I do this. As of now I am using

strippedList = re.sub(r'\W+', '', origList)

And why are you not happy with your current solution? – unwind May 06 '10 at 08:05 — unwind, May 06 '10 at 08:05
Ah I just needed to change '' to ' '. fail Thanks man – j00niner May 06 '10 at 08:07 — j00niner, May 06 '10 at 08:07

score 47 · Answer 1 · answered May 06 '10 at 08:09

47

re.sub(r'([^\s\w]|_)+', '', origList)

answered May 06 '10 at 08:09

Ignacio Vazquez-Abrams

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Just as a note, that '|_' will slow down your regex. (Won't matter if the input is small, of course.) – Alice Purcell May 06 '10 at 10:02
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@Ignacio, what is `|_` doing here? – CKM May 15 '18 at 06:17
@chandresh: Undoing the exclusion in `^\w`. – Ignacio Vazquez-Abrams May 15 '18 at 07:03
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I think I come to this answer at least once every week. – Arthur Camara Sep 30 '19 at 10:52

score 10 · Answer 2 · answered Sep 23 '12 at 18:44

10

A bit faster implementation:

import re

pattern = re.compile('([^\s\w]|_)+')
strippedList = pattern.sub('', value)

answered Sep 23 '12 at 18:44

pata kusik

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score 8 · Answer 3 · answered May 06 '10 at 08:11

The regular-expression based versions might be faster (especially if you switch to using a compiled expression), but I like this for clarity:

"".join([c for c in origList if c in string.letters or c in string.whitespace])

It's a bit weird with the join() call, but I think that is pretty idiomatic Python for converting a list of characters into a string.

score 1 · Answer 4 · answered May 06 '10 at 11:16

Demonstrating what characters you will get in the result:

>>> s = ''.join(chr(i) for i in range(256)) # all possible bytes
>>> re.sub(r'[^\s\w_]+','',s) # What will remain
'\t\n\x0b\x0c\r 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz'

Docs: re.sub, Regex HOWTO: Matching Characters, Regex HOWTO: Repeating Things

Python: Strip everything but spaces and alphanumeric

4 Answers4

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