反转字典中键/值对的顺序(Python) [英] Reversing the order of key-value pairs in a dictionary (Python)

问题描述

如何在Python中颠倒字典的键值对的顺序?例如，我有这本字典:

How do I reverse the order of key-value pairs of a dictionary, in Python? For example, I have this dictionary:

{"a":1, "b":2, "c":3}

我想反转它，以便返回:

I want to reverse it so that it returns:

{"c":3, "b":2, "a":1}

有没有我听说过的功能可以做到这一点?一些代码行也可以.

Is there a function that I haven't heard about that can do this? Some lines of code is fine as well.

推荐答案

字典没有任何顺序感，因此您的键/值对不以任何格式排序.

Dictionary does not have any sense of order , so your key/value pairs are not ordered in any format.

如果要保留键的顺序，则应使用从一开始就是 collections.OrderedDict ，而不是使用普通字典，示例-

If you want to preserve the order of the keys, you should use collections.OrderedDict from the start, instead of using normal dictionary , Example -

>>> from collections import OrderedDict
>>> d = OrderedDict([('a',1),('b',2),('c',3)])
>>> d
OrderedDict([('a', 1), ('b', 2), ('c', 3)])

OrderedDict将保留键在字典中输入的顺序.在上述情况下，这就是键在列表中的存在顺序- [('a'，1)，('b'，2)，('c'，3)] -'a'->'b'->'c'

OrderedDict would preserve the order in which the keys were entered into the dictionary. In above case, it would be the order in which the keys existed in the list - [('a',1),('b',2),('c',3)] - 'a' -> 'b' -> 'c'

然后您可以使用 reversed(d)(示例-

Then you can get the reversed order of keys using reversed(d) , Example -

>>> dreversed = OrderedDict()
>>> for k in reversed(d):
...     dreversed[k] = d[k]
...
>>> dreversed
OrderedDict([('c', 3), ('b', 2), ('a', 1)])

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