如何对 Python 中具有相同名称的元组的值求和 [英] How to sum values of tuples that have same name in Python

问题描述

我有以下包含必须为值的元组的列表:

mylist=[(3, 'a'), (2, 'b'), (4, 'a'), (5, 'c'), (2, 'a'), (1, 'b')]

有没有办法对所有具有相同名称的值求和?类似的东西:

(9, 'a'), (3, 'b'), (5, 'c')

我尝试用 for 循环迭代元组，但无法得到我想要的.

谢谢

解决方案

您可以使用 itertools.groupby(按每个元组的第二个值排序后)来创建组.然后对于每个组，对每个元组中的第一个元素求和，然后在列表理解中为每个组创建一个元组.

<预><代码>>>>导入迭代工具>>>[(sum(i[0] for i in group), key) for key, group in itertools.groupby(sorted(mylist, key = lambda i: i[1]), lambda i: i[1])][(9, 'a'), (3, 'b'), (5, 'c')]

I have the following list containing tuples that have to values:

mylist=[(3, 'a'), (2, 'b'), (4, 'a'), (5, 'c'), (2, 'a'), (1, 'b')]

Is there a way to sum all values that share the same name? Something like:

(9, 'a'), (3, 'b'), (5, 'c')

I tried iterating tuples with for loop but can't get what i want.

Thank you

解决方案

You can use itertools.groupby (after sorting by the second value of each tuple) to create groups. Then for each group, sum the first element in each tuple, then create a tuple per group in a list comprehension.

>>> import itertools
>>> [(sum(i[0] for i in group), key) for key, group in itertools.groupby(sorted(mylist, key = lambda i: i[1]), lambda i: i[1])]
[(9, 'a'), (3, 'b'), (5, 'c')]

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