python: pointwise list sum

问题

Input: two lists (list1, list2) of equal length
Output: one list (result) of the same length, such that:
    result[i] = list1[i] + list2[i]

Is there any concise way to do that? Or is this the best:

# Python 3
assert len(list1) == len(list2)
result = [list1[i] + list2[i] for i in range(len(list1))]

回答1:

You can use the builtin zip function, or you can also use do it mapping the two lists over the add operator. Like this:

from operator import add
map(add, list1,list2)

回答2:

IMO the nicest way is

result = [x + y for x, y in zip(list1, list2)]

with Python3 basic zip is not even building an intermediate list (not an issue unless list1 and list2 lists are huge).

Note however that zip will stop at the shortest of the input lists, so your assert is still needed.

回答3:

[a + b for a, b in zip(list1, list2)]

回答4:

There are several ways, e.g. using map, sum and izip (but afaik, zip works the same as izip in Python 3):

>>> from itertools import izip
>>> map(sum, izip(list1, list2))

回答5:

I'd do:

result = [x+x for x,y in zip(list1, list2)]

来源：https://stackoverflow.com/questions/5788470/python-pointwise-list-sum