问题：字典元组列表
这是我目前在Python中将元组列表转换为字典的方式：
l = [('a',1),('b',2)]
h = {}
[h.update({k:v}) for k,v in l]
> [None, None]
h
> {'a': 1, 'b': 2}
有没有更好的办法？似乎应该有一种做法。
Here’s how I’m currently converting a list of tuples to dictionary in Python:
l = [('a',1),('b',2)]
h = {}
[h.update({k:v}) for k,v in l]
> [None, None]
h
> {'a': 1, 'b': 2}
Is there a better way? It seems like there should be a one-liner to do this.
回答 0
只需dict()直接调用元组列表
>>> my_list = [('a', 1), ('b', 2)]
>>> dict(my_list)
{'a': 1, 'b': 2}
Just call dict() on the list of tuples directly
>>> my_list = [('a', 1), ('b', 2)]
>>> dict(my_list)
{'a': 1, 'b': 2}
回答 1
该dict构造函数接受输入的完全一样，你把它（键/值元组）。
>>> l = [('a',1),('b',2)]
>>> d = dict(l)
>>> d
{'a': 1, 'b': 2}
从文档中：
例如，所有这些都返回等于{“ one”：1，“ two”：2}的字典：
dict(one=1, two=2)
dict({'one': 1, 'two': 2})
dict(zip(('one', 'two'), (1, 2)))
dict([['two', 2], ['one', 1]])
The dict constructor accepts input exactly as you have it (key/value tuples).
>>> l = [('a',1),('b',2)]
>>> d = dict(l)
>>> d
{'a': 1, 'b': 2}
From the documentation:
For example, these all return a
dictionary equal to {“one”: 1, “two”:
2}:
dict(one=1, two=2)
dict({'one': 1, 'two': 2})
dict(zip(('one', 'two'), (1, 2)))
dict([['two', 2], ['one', 1]])
回答 2
具有dict理解力：
h = {k:v for k,v in l}
With dict comprehension:
h = {k:v for k,v in l}
回答 3
似乎每个人都假定元组列表在键和值之间具有一对一的映射关系（例如，它没有字典的重复键）。由于这是在该主题上搜索的第一个问题，因此我针对一个更常见的情况发布了答案，在这种情况下，我们必须处理重复项：
mylist = [(a,1),(a,2),(b,3)]
result = {}
for i in mylist:
result.setdefault(i[0],[]).append(i[1])
print(result)
>>> result = {a:[1,2], b:[3]}
It seems everyone here assumes the list of tuples have one to one mapping between key and values (e.g. it does not have duplicated keys for the dictionary). As this is the first question coming up searching on this topic, I post an answer for a more general case where we have to deal with duplicates:
mylist = [(a,1),(a,2),(b,3)]
result = {}
for i in mylist:
result.setdefault(i[0],[]).append(i[1])
print(result)
>>> result = {a:[1,2], b:[3]}
