如何按值排序Python dict [英] How to sort a Python dict by value

问题描述

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

我想将它转换成DESC并创建一个关键字列表。例如，这将返回

[keyword3，keyword1，keyword4，keyword2]

我发现使用lambda的所有示例，我并不是很强。有没有一种方法可以循环遍历，并按照我们的方式进行排序？感谢任何建议。

PS：如果有帮助，我可以创建初始的dict。

解决方案

您可以使用

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

（您不需要 code> in Python 2.x）

theDict .__ getitem __ 实际上相当于 lambda x：theDict [x] 。

（lambda只是一个匿名函数，例如

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

这相当于

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

）

I have a dict that looks like this

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

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

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

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

解决方案

You could use

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

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

The theDict.__getitem__ is actually equivalent to lambda x: theDict[x].

(A lambda is just an anonymous function. For example

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

This is equivalent to

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

)

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