Simple Python Regex not matching

Question

Very simply, I am trying to replace a string that contains the substring XX.

import re

def replace_bogus(original, replacement):
    bogus = re.compile('[.]*[X][X][.]*')
    if bogus.match(original) != None:
        original = replacement

    return original

if __name__ == "__main__":
    teststr = replace_bogus('ABXX0123', '')
    print teststr

This code prints out ABXX0123. Why is this regex wrong and what should I use instead?

re module have it's own sub method for replacing.

Reloader
– Reloader

2014-06-19 15:38:28 +00:00
Commented Jun 19, 2014 at 15:38 — Reloader
– Reloader, Commented Jun 19, 2014 at 15:38

Amal · Accepted Answer · 2014-06-19 15:41:31Z

3

Because the dot (.) has no special meaning when it's inside a character class (i.e. [.]). The regex doesn't match the text and it returns None.

As has been said in the comments, the re module has its own method for replacing, i.e. the sub method. You can simply use it like so:

import re
p = re.compile(r'XX')
result = re.sub(p, '', 'ABXX0123')
print result // => AB0123

answered Jun 19, 2014 at 15:41

Amal

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1 Comment

David Ehrmann Over a year ago

Adding to that, I've put dots in characters classes because it can be clearer than backslash hell, but doing it for X doesn't make any sense.

Andre Scholich · Accepted Answer · 2014-06-19 15:50:38Z

0

As you did not state that you want to use regexp. What about:

teststr = 'ABXX0123'
print teststr.replace('XX', '')

answered Jun 19, 2014 at 15:50

Andre Scholich

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