Python: Sum string lengths

Question

Is there a more idiomatic way to sum string lengths in Python than by using a loop?

length = 0
for string in strings:
    length += len(string)

Answer 1

length = sum(len(s) for s in strings)

Answer 2

Just to add upon ...

Adding numbers from a list stored as a string

nos = ['1','14','34']

length = sum(int(s) for s in nos)

Answer 3

The shortest and fastest way is apply a functional programming style with map() and sum():

>>> data = ['a', 'bc', 'def', 'ghij']
>>> sum(map(len, data))
10

In Python 2, use itertools.imap instead of map for better memory performance:

>>> from itertools import imap
>>> data = ['a', 'bc', 'def', 'ghij']
>>> sum(imap(len, data))
10

Answer 4

print(sum(len(mystr) for mystr in strings))

Answer 5

My first way to do it would be sum(map(len, strings)). Another way is to use a list comprehension or generator expression as the other answers have posted.

Answer 6

I know this is an old question, but I can't help noting that the Python error message tells you how to do this:

TypeError: sum() can't sum strings [use ''.join(seq) instead]

So:

>>> strings = ['abc', 'de']
>>> print len(''.join(strings))
5