返回字典中常用值的键字典

Question

我想返回另一个字典中多次出现的元素键的字典。

例：

x = {1:10, 2:12, 3:14, 4:10, 5:14} 

答案会返回

{10:[1,4], 14:[3,5]} 

Answer 1

这是想到的最简单的解决方案

x = {1: 10, 2: 12, 3: 14, 4: 10, 5: 14}
res = {}
for k, v in x.items():
    temp = res.setdefault(v, [])
    temp.append(k)
res = {k: v for k, v in res.items() if len(v)>1}
print(res)  # {10: [1, 4], 14: [3, 5]}

我想知道itertools.groupby()是否可以以某种方式在这里使用..

Answer 2

这个

怎么样

# python 2.x
x = {1:10, 2:12, 3:14, 4:10, 5:14} 
a = {}
for key, value in x.iteritems():  # x.items() if python 3.x
    a.setdefault(key, []).append(value)
for key, value in x.iteritems():
    if len(value) <= 1
        a.pop(key, None)
print a

Answer 3

x = {1:10, 2:12, 3:14, 4:10, 5:14} 
res = {}
for k, v in x.iteritems():
    res[v] = res.get(v, [])
    res[v].append(k)
{k: v for k, v in res.items() if len(v) > 1}