Regular expression with [ or ( in python

Question

I need to extract IP address in the form

prosseek.amer.corp.com [10.0.40.147]

or

prosseek.amer.corp.com (10.0.40.147)

with Python. How can I get the IP for either case with Python? I started with something like

site = "prosseek.amer.corp.com"
m = re.search("%s.*[\(\[](\d+\.\d+\.\d+\.\d+)" % site, r)

but it doesn't work.

ADDED

m = re.search("%s.+(\(|\[)(\d+\.\d+\.\d+\.\d+)" % site, r)
m.group(2)
m = re.search(r"%s.*[([](\d+\.\d+\.\d+\.\d+)" % site, r)
m.group(1)

seems to work.

Answer 1

You don't need to escape meta-characters (*, (, ), ., ...) in character groups (except ], unless it is the first character in the character group; [][]+ would match a sequence of square brackets.)

Another tip when it comes to Python is to use r'...'-style strings. With them, backslashes has no special meaning. r'\\' would print \\, since backslash has no special meaning:

m = re.search(r"%s.*[([](\d+\.\d+\.\d+\.\d+)" % site, r)

In the above string it doesn't make any difference though, since \d doesn't mean anything in Python, but when it comes to stuff like \r, \\, etc., it makes lives easier.