How can I prepend http to a url if it doesn't begin with http?

Question

I have urls formatted as:

google.com
www.google.com
http://google.com
http://www.google.com

I would like to convert all type of links to a

Answer 1

I found it easy to detect the protocol with regex and then append it if missing:

import re
def formaturl(url):
    if not re.match('(?:http|ftp|https)://', url):
        return 'http://{}'.format(url)
    return url

url = 'test.com'
print(formaturl(url)) # http://test.com

url = 'https://test.com'
print(formaturl(url)) # https://test.com

I hope it helps!