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python: how to sort a complex list on two different keys
我有一个元组列表.我想根据两个元素对它们进行排序.下面是一个例子
unsorted = [('a', 4, 2), ('a', 4, 3), ('a', 7, 2), ('a', 7, 3), ('b', 4, 2), ('b', 4, 3), ('b', 7, 2), ('b', 7, 3)]
sorted = [('a', 4, 2), ('b', 4, 2), ('a', 4, 3), ('b', 4, 3), ('a', 7, 2), ('b', 7, 2), ('a', 7, 3), ('b', 7, 3)]
我知道如何根据第二个元素对它们进行排序:
sorted(unsorted, key = lambda element : element[1])
但是用两把 keys 怎么做呢？