python - String length without len function

Question

Can anyone tell me how can I get the length of a string without using the len() function or any string methods. Please anyone tell me as I'm tapping my head madly for the answer.
Thank you.

Answer 1

>>> sum(map(lambda x:1, "hello world"))
11

>>> sum(1 for x in "foobar")
6

>>> from itertools import count
>>> zip(count(1), "baz")[-1][0]
3

A "tongue twister"

>>> sum(not out not in out for out in "shake it all about")
18

some recursive solutions

>>> def get_string_length(s):
...     return 1 + get_string_length(s[1:]) if s else 0
... 
>>> get_string_length("hello world")
11
>>> def get_string_length_gen(s):
...     yield 1 + next(get_string_length_gen(s[1:])) if s else 0
... 
>>> next(get_string_length_gen("hello world"))
11
>>>