如何在 Python 的元组列表中对每个元组中的第一个值求和?

问题描述

我有一个这样的元组列表(总是对):

[(0, 1), (2, 3), (5, 7), (2, 1)]

我想找到每对中第一项的总和，即:

0 + 2 + 5 + 2

如何在 Python 中做到这一点?目前我正在遍历列表:

sum = 0对于 list_of_pairs 中的对:总和 += 对[0]

我觉得肯定有一种更 Pythonic 的方式.

解决方案

在 Python 的现代版本中，我建议 SilentGhost 发布的内容(为了清楚起见在此重复):

<块引用>

sum(i for i, j in list_of_pairs)

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在此答案的早期版本中，我曾建议这样做，这是必要的，因为 SilentGhost 的版本在当时最新的 Python (2.3) 版本中不起作用:

sum([pair[0] for list_of_pairs])

现在那个版本的 Python 已经过时了，而且 SilentGhost 的代码适用于所有当前维护的 Python 版本，所以不再有任何理由推荐我最初发布的版本.

I have a list of tuples (always pairs) like this:

[(0, 1), (2, 3), (5, 7), (2, 1)]

I'd like to find the sum of the first items in each pair, i.e.:

0 + 2 + 5 + 2

How can I do this in Python? At the moment I'm iterating through the list:

sum = 0
for pair in list_of_pairs:
   sum += pair[0]

I have a feeling there must be a more Pythonic way.

解决方案

In modern versions of Python I'd suggest what SilentGhost posted (repeating here for clarity):

sum(i for i, j in list_of_pairs)

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In an earlier version of this answer I had suggested this, which was necessary because SilentGhost's version didn't work in the version of Python (2.3) that was current at the time:

sum([pair[0] for pair in list_of_pairs])

Now that version of Python is beyond obsolete, and SilentGhost's code works in all currently-maintained versions of Python, so there's no longer any reason to recommend the version I had originally posted.