python如何删除dict中重复value值的item

Question

字典 z 如下

z = {
    1: 'a',
    2: 'a',
    3: 'a',
    4: 'b',
    5: 'c',
    6: 'c',
    7: 'd'
}

要求删除重复的 value 的 item，只保留一个，如何实现？

Answer 1

tuple_r_dict = lambda _dict: dict(val[::-1] for val in _dict.iteritems()) # _dict.items() in Python3.x

tuple_r_dict(tuple_r_dict(z))

or

values=set()
for key in z.keys():
    val = z[key]
    if val in values: 
        del z[key]
    else:
        values.add(val)