python - 如何合并字典，从匹配的键中收集值？

Question

我有多个这样的字典(或键值对序列):

d1 = {key1: x1, key2: y1}
d2 = {key1: x2, key2: y2}

我怎样才能有效地得到这样的结果，作为一个新的字典？

d = {key1: (x1, x2), key2: (y1, y2)}

Answer 1

这是一个通用的解决方案，可以处理任意数量的字典，当键仅在一些字典中时:

from collections import defaultdict

d1 = {1: 2, 3: 4}
d2 = {1: 6, 3: 7}

dd = defaultdict(list)

for d in (d1, d2): # you can list as many input dicts as you want here
    for key, value in d.items():
        dd[key].append(value)
    
print(dd) # result: defaultdict(<type 'list'>, {1: [2, 6], 3: [4, 7]})