python怎样对字典排序？

Question

有一字典{"A":5,"C":4,"B":10,"D":20}
怎样最快对这个字典按照value降序排列，变成{“D”:20,"B":10,"A":5,"C":4}?

Answer 1

dic = {"A":5,"C":4,"B":10,"D":20}
print(sorted(dic.items(), key=lambda a: a[1], reverse=True))

Answer 2

字典本身是无序的，需要先转成元组再排序如下：

a={"A":5,"C":4,"B":10,"D":20}
import operator
# 按值排序排序
b=sorted(a.items(),key=operator.itemgetter(1),reverse = True )
print(b)