Using a RegEx to match IP addresses

I’m trying to make a test for checking whether a sys.argv input matches the RegEx for an IP address…

As a simple test, I have the following…

import re

pat = re.compile("d{1,3}.d{1,3}.d{1,3}.d{1,3}")
test = pat.match(hostIP)
if test:
   print "Acceptable ip address"
else:
   print "Unacceptable ip address"

However when I pass random values into it, it returns “Acceptable IP address” in most cases, except when I have an “address” that is basically equivalent to d+.

Answer

You have to modify your regex in the following way

pat = re.compile("^d{1,3}.d{1,3}.d{1,3}.d{1,3}$")

that’s because . is a wildcard that stands for “every character”