对元组列表中的每个值求和

Question

我有一个与此类似的元组列表:

l = [(1, 2), (3, 4), (5, 6), (7, 8), (9, 0)]

我想创建一个简单的单行程序,它会给我以下结果:

r = (25, 20) or r = [25, 20] # don't care if tuple or list.

这就像做以下事情:

r = [0, 0]
for t in l:
  r[0]+=t[0]
  r[1]+=t[1]

我确信这很简单,但我想不出来.

注意:我已经查看了类似的问题:

如何将元组中的一组列表中的第一个值相加？

如何在Python中的元组列表中对每个元组中的第一个值求和？

Answer 1

使用zip()和sum():

In [1]: l = [(1, 2), (3, 4), (5, 6), (7, 8), (9, 0)]

In [2]: [sum(x) for x in zip(*l)]
Out[2]: [25, 20]

要么:

In [4]: map(sum, zip(*l))
Out[4]: [25, 20]

timeit 结果:

In [16]: l = [(1, 2), (3, 4), (5, 6), (7, 8), (9, 0)]*1000

In [17]: %timeit [sum(x) for x in zip(*l)]
1000 loops, best of 3: 1.46 ms per loop

In [18]: %timeit [sum(x) for x in izip(*l)]       #prefer itertools.izip
1000 loops, best of 3: 1.28 ms per loop

In [19]: %timeit map(sum, zip(*l))
100 loops, best of 3: 1.48 ms per loop

In [20]: %timeit map(sum, izip(*l))                #prefer itertools.izip
1000 loops, best of 3: 1.29 ms per loop