Python删除字典上具有相同值的键 [英] Python remove keys with the same value on a dictionary

问题描述

我需要对字典执行非自然操作，所以我想知道什么是最好的pythonic方法。

I need to do a not "natural" operation on a dictionary so i wondering what is the best pythonic way to do this.

我需要简化字典通过删除所有具有相同值的键（键不同，值相同）

I need to simplify a dictionary by removing all the keys on it with the same value (keys are differents, values are the same)

例如：
输入：

For example: Input:

  dict = {key1 : [1,2,3], key2: [1,2,6], key3: [1,2,3]}

预期产量：

  {key1 : [1,2,3], key2:[1,2,6]}

我不在乎删除哪个键（例如：key1或key3）

I dont care about which key is delete (on the example: key1 or key3)

推荐答案

交换键和值；重复的键值对将被删除，这是一个副作用（因为字典不允许重复的键）。再次交换键和值。

Exchange keys and values; duplicated key-value pairs will be removed as a side effect (because dictionary does not allow duplicated keys). Exchange keys and values again.

>>> d = {'key1': [1,2,3], 'key2': [1,2,6], 'key3': [1,2,3]}
>>> d2 = {tuple(v): k for k, v in d.items()}  # exchange keys, values
>>> d = {v: list(k) for k, v in d2.items()}   # exchange again
>>> d
{'key2': [1, 2, 6], 'key1': [1, 2, 3]}

注意：之所以使用 tuple（v）是因为 list 是不可散列的；不能直接用作键。

NOTE: tuple(v) was used because list is not hashable; cannot be used as key directly.

顺便说一句，请勿使用 dict 作为变量名。它将隐藏内置函数/类型 dict 。

BTW, don't use dict as a variable name. It will shadow builtin function/type dict.

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