python - 根据元组列表中的某个键组合公共(public)值

Question

例如

data = [ (item1, ('1-jan' ,45)) , (item2, ('21-jan',65)), (item1, ('21-jan',48))]

我喜欢这样的东西:

result = [ (item1, [('1-jan' ,45),('21-jan',48)]), (item2, [('21-jan',65)])]

准确地说，我需要最终结果

result = { item1: ('1-jan':45,'21-jan':48)), item2: ('21-jan':65)]

Answer 1

您可以使用 dict.setdefault()在字典中轻松创建分组:

>>> data = [ ('item1', ('1-jan' ,45)) , ('item2', ('21-jan',65)), ('item1', ('21-jan',48))]
>>> result = {}
>>> for k, v in data:
        result.setdefault(k, []).append(v)

>>> result
{'item2': [('21-jan', 65)], 'item1': [('1-jan', 45), ('21-jan', 48)]}

您还可以使用 collections.defaultdict达到同样的目的。