Question

如果我有2个列表：

fruits = ["apple","apple","oranges","watermelon","apple"]
val = ["a","b","c","d","e"]

val的每个索引对应于水果的索引

因此，如果我要使用以下字典：

dict
{
"apple" : ["a","b","e"],
"oranges": ["c"],
"watermelon": ["d"]
}

最简单的方法是什么？

Answer 1

使用带有defaultdict工厂的list作为输出容器，并使用zip遍历两个列表：

In [162]: out = collections.defaultdict(list)

In [163]: for k, v in zip(fruits, val):
     ...:     out[k].append(v)
     ...:     

In [164]: out
Out[164]: 
defaultdict(list,
            {'apple': ['a', 'b', 'e'], 'oranges': ['c'], 'watermelon': ['d']})

In [165]: dict(out)
Out[165]: {'apple': ['a', 'b', 'e'], 'oranges': ['c'], 'watermelon': ['d']}

Answer 2

您可以使用setdefault用一个空列表初始化每个值，然后附加另一个列表中的值

fruits = ["apple","apple","oranges","watermelon","apple"]
val = ["a","b","c","d","e"]
d={}

for k, v in zip(fruits, val):
    d.setdefault(k, []).append(v) 

print(d)
# {'apple': ['a', 'b', 'e'], 'oranges': ['c'], 'watermelon': ['d']}

Python 2.7：将两个具有重复值的列表放入字典

2 个答案: