从列表创建简单字典

Question

Sorry for asking a simple question:

I have the following list:

 x = ["one", "two", "three" ]

What is the best way to create this dictionary:

 {"one":1, "two":1, "three":1 }

Thanks

Answer 1

使用字典理解 ：

{key: 1 for key in x}

Answer 2

print dict.fromkeys(["one","two","three"],1)

Is how I would do it ... if you really just want to make a dict from a list (to speed up searches maybe)

if you dont care what the value is you can just do

print dict.fromkeys(["one","two","three"])

and it will be the default None

this has the added benefit of working for python < 2.7 plus it is very easy to tell what you are doing , where as dict comprehensions always make me think of set comprehensions

Answer 3

I'm going to extrapolate and guess that you're looking for a Counter :

>>> from collections import Counter
>>> x = ["one", "two", "three" ]
>>> Counter(x)
Counter({'three': 1, 'two': 1, 'one': 1})