How to remove symbols from a string with Python?


Question

I'm a beginner with both Python and RegEx, and I would like to know how to make a string that takes symbols and replaces them with spaces. Any help is great.

For example:

how much for the maple syrup? $20.99? That's ricidulous!!!

into:

how much for the maple syrup 20 99 That s ridiculous
1
63
5/18/2009 1:55:37 AM

Accepted Answer

One way, using regular expressions:

>>> s = "how much for the maple syrup? $20.99? That's ridiculous!!!"
>>> re.sub(r'[^\w]', ' ', s)
'how much for the maple syrup   20 99  That s ridiculous   '
  • \w will match alphanumeric characters and underscores

  • [^\w] will match anything that's not alphanumeric or underscore

117
6/4/2017 5:59:12 PM

Sometimes it takes longer to figure out the regex than to just write it out in python:

import string
s = "how much for the maple syrup? $20.99? That's ricidulous!!!"
for char in string.punctuation:
    s = s.replace(char, ' ')

If you need other characters you can change it to use a white-list or extend your black-list.

Sample white-list:

whitelist = string.letters + string.digits + ' '
new_s = ''
for char in s:
    if char in whitelist:
        new_s += char
    else:
        new_s += ' '

Sample white-list using a generator-expression:

whitelist = string.letters + string.digits + ' '
new_s = ''.join(c for c in s if c in whitelist)

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