在dict for Python中通过值查找键

Question

NAMES  =  ['Alice', 'Bob','Cathy','Dan','Ed','Frank',
           'Gary','Helen','Irene','Jack', 'Kelly','Larry'] 
AGES  =  [20,21,18,18,19,20,20,19,19,19,22,19]

def nameage(a,b):
    nameagelist = [x for x in zip(a,b)]
    nameagedict = dict(nameagelist)

    return nameagedict

def name(a):
    for x in nameage(NAMES,AGES):
        if a in nameage(NAMES,AGES).values():
            print nameage(NAMES,AGES).keys()

print name(19)

我想把19岁的人的名字还给你。如何按值搜索词典并返回密钥？

Answer 1

print [key for (key,value) in nameagedict.items() if value == 19]

nameagedict.items()以（键，值）元组的形式提供字典中所有项的列表。