CODEWITHSUNDEEP
pythonregexpython-2.6
Sok
Sok

Reputation: 303

Python regular expressions inside parenthesis

I'm having some trouble when trying to some get some data from within parenthesis. Here's some sample code:

import re    
test_string = '123a (456b)'
regex_a = re.match(r'(?P<a>\d+)a', test_string)
regex_b = re.match(r'(?P<b>\d+)b', test_string)
print regex_a
print regex_b

I would have expected the two regex objects to come back with 123 and 456 respectively, but regex_b returns None. Here's a python fiddle showing it (not) working: http://pythonfiddle.com/regex-in-parenthesis

I also tried this in Pythex too (here's a link), but in that environment it works!

I'm scratching my head as to what's going on, any help you could give me would be greatly appreciated. I'm using python 2.6 if that makes a difference.

Upvotes: 1

Views: 264

Answers (2)

Kasravnd
Kasravnd

Reputation: 107347

If you want to match the number within parenthesis you can use the following regex :

\((\d+).*\)

Note that you need to escape the parenthesis and use capture grouping for your digit combination (\d+),also Note that re.match checks for a match only at the beginning of the string,instead you need to use re.search :

>>> re.search(r'\((\d+).*\)',test_string).group(1)
'456'

And if you want to find all numbers you can use re.findall :

>>> re.findall(r'\d+',test_string)
['123', '456']

Upvotes: 1

user2034412
user2034412

Reputation: 4282

re.match() only matches from the beginning of the string. Try re.search() instead.

Upvotes: 2

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