Concatenate lists of strings item-wise in Python

Question

This is a tips question for golfing in python.

Suppose you have two lists of strings, and you want to concatenate the corresponding entries from each list. E.g. with a=list("abcd") and b=list("1234"), calculate ["a1","b2","c3","d4"].

This is trivial in array-based programming languages, where operations generally apply memberwise to lists. For example, in my golfing language Pip, the code is simply a.b. But in Python, it's not so easy.

The Pythonic way is probably to use zip and a list comprehension (25 chars):

[x+y for x,y in zip(a,b)]

Another method is map with a lambda function (23):

map(lambda x,y:x+y,a,b)

The following is the shortest I've come up with (21):

map("".join,zip(a,b))

Is there any shorter method?

Assume that the lists are the same length and that some kind of iterable is all that's needed (so a map object is fine in Python 3).

Answer 1

20 chars

map(str.__add__,a,b)

Uses the build-in method string addition method __add__ that is invoked by + on strings in place of your anonymous function lambda x,y:x+y.