What is the most efficient way to check if an URL is valid/exists?

Question

I'm looking for the fastest method to retrieve whether or not an URL exists. I'd like to do the test on a list of URLs.

Thanks for your help

Answer 1

import httplib
c = httplib.HTTPConnection('www.stackoverflow.com')
c.request("HEAD", '')
if c.getresponse().status == 301:
   print('Good news. Website is valid')