如何按值对Python字典的键进行排序 [英] How to sort a Python dict's keys by value

问题描述

我有一个像这样的字典

{ "keyword1":3 , "keyword2":1 , "keyword3":5 , "keyword4":2 }

我想将其转换为DESC并创建仅包含关键字的列表.例如，这将返回

And I would like to convert it DESC and create a list of just the keywords. Eg, this would return

["keyword3" , "keyword1" , "keyword4" , "keyword2"]

我发现的所有示例都使用lambda，但我对此并不十分坚决.有什么办法可以让我循环浏览，并随时对其进行排序?感谢您的任何建议.

All examples I found use lambda and I'm not very strong with that. Is there a way I could loop through this, and sort them as I go? Thanks for any suggestions.

PS:如果有帮助的话，我可以以不同的方式创建初始字典.

PS: I could create the initial dict differently if it would help.

推荐答案

您可以使用

res = list(sorted(theDict, key=theDict.__getitem__, reverse=True))

(在Python 2.x中不需要list)

(You don't need the list in Python 2.x)

theDict.__getitem__实际上等效于lambda x: theDict[x].

(lambda只是一个匿名函数.例如

(A lambda is just an anonymous function. For example

>>> g = lambda x: x + 5
>>> g(123)
128

这等效于

>>> def h(x):
...   return x + 5
>>> h(123)
128

)

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