在这种情况下python中的sum函数如何工作（加和一个列表的元组）

Question

I am trying to use sum() function in my code, but there is an error, which i did not understand why. How can i solve this problem

my code should add up tuples of a list so the output should be like this

the input:

a = [(1, 2, 3), (4, 5, 6)]

the output:

(5, 7, 9)

this is my code

a = [(1, 3, 5), (2, 3, 5), (3, 3, 5), (4, 3, 5)]
a = iter(a)
b = next(a)
for x in a:
    b = sum(b, x)
print(b)

The error is:

TypeError: can only concatenate tuple (not "int") to tuple

Answer 1

This can be done using the zip builtin function:

[sum(x) for x in zip(*a)]

Full console session:

>>> a = [(1, 2, 3), (4, 5, 6)]
>>> list(zip(*a))  # "Make an iterator that aggregates elements from each of the iterables"
[(1, 4), (2, 5), (3, 6)]
>>> [sum(x) for x in zip(*a)]
[5, 7, 9]
>>>