Question

I know I can count the leading spaces in a string with this:

>>> a = "   foo bar baz qua   \n"
>>> print "Leading spaces", len(a) - len(a.lstrip())
Leading spaces 3
>>>

But is there a more pythonic way?

Answer 1

Your way is pythonic but incorrect, it will also count other whitespace chars, to count only spaces be explicit a.lstrip(' '). Compare

a = "   \r\t\n\tfoo bar baz qua   \n"
print("Leading spaces", len(a) - len(a.lstrip()))

>>> Leading spaces 7

and

print("Leading spaces", len(a) - len(a.lstrip(' '))

>>> Leading spaces 3