Python字典递减排序

Question

我想排序我的字典递减。

dic = { "one" = 5, "two" = 8, "three" = 1, "four" = 3} 

输出应该是：

("two", 8) 
("one", 5) 
("four", 3) 
("three", 1) 

什么是最简单的方法是什么？

Answer 1

sorted支持关键字reverse。将其设置为True以获得颠倒的排序顺序。

>>> dic = {"one": 5, "two": 8, "three": 1, "four": 3} 

一种方式：

>>> [(k, dic[k]) for k in sorted(dic, key=dic.get, reverse=True)] 
[('two', 8), ('one', 5), ('four', 3), ('three', 1)] 

或：

>>> from operator import itemgetter 
>>> sorted(dic.items(), key=itemgetter(1), reverse=True) 
[('two', 8), ('one', 5), ('four', 3), ('three', 1)] 

这里itemgetter(1)确实相同lambda x: x[1]，这又相当于：

def get_index_one(x): 
    return x[1] 

即

>>> sorted(dic.items(), key=get_index_one, reverse=True) 
[('two', 8), ('one', 5), ('four', 3), ('three', 1)] 

Answer 2

稍微不同的方式：

>>> dic = { "one" : 5, "two" : 8, "three" : 1, "four" : 3} 
>>> sorted(dic.items(), key = lambda x:x[1],reverse = True) 
[('two', 8), ('one', 5), ('four', 3), ('three', 1)]