Grab a line's whitespace/indention with Python

Question

Basically, if I have a line of text which starts with indention, what\'s the best way to grab that indention and put it into a variable in Python? For example, if the line i

Answer 1

This can also be done with str.isspace and itertools.takewhile instead of regex.

import itertools

tests=['\t\tthis line has two tabs of indention',
       '    this line has four spaces of indention']

def indention(astr):
    # Using itertools.takewhile is efficient -- the looping stops immediately after the first
    # non-space character.
    return ''.join(itertools.takewhile(str.isspace,astr))

for test_string in tests:
    print(indention(test_string))