Get the string within brackets in Python

41

I have a sample string <alpha.Customer[cus_Y4o9qMEZAugtnW] active_card=<alpha.AlphaObject[card] ...>, created=1324336085, description='Customer for My Test App', livemode=False>

I only want the value cus_Y4o9qMEZAugtnW and NOT card (which is inside another [])

How could I do it in easiest possible way in Python? Maybe by using RegEx (which I am not good at)?

This question is tagged with python regex brackets

~ Asked on 2011-12-20 00:00:04

The Best Answer is


82

How about:

import re

s = "alpha.Customer[cus_Y4o9qMEZAugtnW] ..."
m = re.search(r"\[([A-Za-z0-9_]+)\]", s)
print m.group(1)

For me this prints:

cus_Y4o9qMEZAugtnW

Note that the call to re.search(...) finds the first match to the regular expression, so it doesn't find the [card] unless you repeat the search a second time.

Edit: The regular expression here is a python raw string literal, which basically means the backslashes are not treated as special characters and are passed through to the re.search() method unchanged. The parts of the regular expression are:

  1. \[ matches a literal [ character
  2. ( begins a new group
  3. [A-Za-z0-9_] is a character set matching any letter (capital or lower case), digit or underscore
  4. + matches the preceding element (the character set) one or more times.
  5. ) ends the group
  6. \] matches a literal ] character

Edit: As D K has pointed out, the regular expression could be simplified to:

m = re.search(r"\[(\w+)\]", s)

since the \w is a special sequence which means the same thing as [a-zA-Z0-9_] depending on the re.LOCALE and re.UNICODE settings.

~ Answered on 2011-12-20 00:07:21


18

This should do the job:

re.match(r"[^[]*\[([^]]*)\]", yourstring).groups()[0]

~ Answered on 2011-12-20 00:09:13


Most Viewed Questions: