在Python中将两个列表转换为字典

想象一下,你有:

keys = ['name', 'age', 'food']
values = ['Monty', 42, 'spam']

生成以下字典的最简单方法是什么？

a_dict = {'name' : 'Monty', 'age' : 42, 'food' : 'spam'}

Dan Lenski.. 1943

像这样:

>>> keys = ['a', 'b', 'c']
>>> values = [1, 2, 3]
>>> dictionary = dict(zip(keys, values))
>>> print(dictionary)
{'a': 1, 'b': 2, 'c': 3}

Voila :-)成对dict构造函数和zip函数非常有用:https://docs.python.org/3/library/functions.html#func-dict

像这样:

>>> keys = ['a', 'b', 'c']
>>> values = [1, 2, 3]
>>> dictionary = dict(zip(keys, values))
>>> print(dictionary)
{'a': 1, 'b': 2, 'c': 3}

Voila :-)成对dict构造函数和zip函数非常有用:https://docs.python.org/3/library/functions.html#func-dict

试试这个:

>>> import itertools
>>> keys = ('name', 'age', 'food')
>>> values = ('Monty', 42, 'spam')
>>> adict = dict(itertools.izip(keys,values))
>>> adict
{'food': 'spam', 'age': 42, 'name': 'Monty'}

在Python 2中,与内存消耗相比,它在内存消耗方面也更经济zip.

想象一下,你有:

keys = ('name', 'age', 'food')
values = ('Monty', 42, 'spam')

生成以下字典的最简单方法是什么？

dict = {'name' : 'Monty', 'age' : 42, 'food' : 'spam'}

使用dict构造函数的一个可能的改进是使用dict理解的本地语法(不是列表理解,正如其他人错误地把它放在一起):

new_dict = {k: v for k, v in zip(keys, values)}

在Python 2中,zip返回一个列表,以避免创建不必要的列表,izip改为使用(别名为zip可以减少代码更改,当你转移到Python 3).

from itertools import izip as zip

所以这仍然是:

new_dict = {k: v for k, v in zip(keys, values)}

Python 2,非常适合<= 2.6

izip从itertools变为zip在Python 3. izip大于拉链用于Python 2(因为它避免了不必要的列表创建)2.6或以下更好,理想的:

from itertools import izip
new_dict = dict(izip(keys, values))

Python 3

在Python 3中,zip变为与itertools模块中相同的功能,因此它只是:

new_dict = dict(zip(keys, values))

然而,字典理解会更高效(请参阅本答案末尾的表现评论).

所有案件的结果:

在所有情况下:

>>> new_dict
{'age': 42, 'name': 'Monty', 'food': 'spam'}

说明:

如果我们查看帮助,dict我们会发现它需要各种形式的参数:

>>> help(dict)

class dict(object)
 |  dict() -> new empty dictionary
 |  dict(mapping) -> new dictionary initialized from a mapping object's
 |      (key, value) pairs
 |  dict(iterable) -> new dictionary initialized as if via:
 |      d = {}
 |      for k, v in iterable:
 |          d[k] = v
 |  dict(**kwargs) -> new dictionary initialized with the name=value pairs
 |      in the keyword argument list.  For example:  dict(one=1, two=2)

>>> zip(keys, values)
[('name', 'Monty'), ('age', 42), ('food', 'spam')]

>>> list(zip(keys, values))
[('name', 'Monty'), ('age', 42), ('food', 'spam')]

>>> zip(keys, values)

generator_expression = ((k, v) for k, v in zip(keys, values))
dict(generator_expression)

dict((k, v) for k, v in zip(keys, values))

dict([(k, v) for k, v in zip(keys, values)])

>>> min(timeit.repeat(lambda: dict(zip(keys, values))))
0.4772876740025822
>>> min(timeit.repeat(lambda: {k: v for k, v in zip(keys, values)}))
0.5217149950040039
>>> min(timeit.repeat(lambda: {keys[i]: values[i] for i in range(len(keys))}))
0.6797661719901953
>>> min(timeit.repeat(lambda: dict([(k, v) for k, v in zip(keys, values)])))
0.7864680950006004
>>> min(timeit.repeat(lambda: dict((k, v) for k, v in zip(keys, values))))
0.8561034000013024

>>> keys = ('name', 'age', 'food')
>>> values = ('Monty', 42, 'spam')
>>> dict(zip(keys, values))
{'food': 'spam', 'age': 42, 'name': 'Monty'}

>>> keys = ('name', 'age', 'food')
>>> values = ('Monty', 42, 'spam')
>>> {k: v for k, v in zip(keys, values)}
{'food': 'spam', 'age': 42, 'name': 'Monty'}

keys = ('name', 'age', 'food')
values = ('Monty', 42, 'spam')    
dict = {keys[i]: values[i] for i in range(len(keys))}

>>> adict = dict((str(k), v) for k, v in zip(['a', 1, 'b'], [2, 'c', 3])) 

keys = ('name', 'age', 'food')
values = ('Monty', 42, 'spam')

dic = {k:v for k,v in zip(keys, values)}

print(dic)

>>> print {i : chr(65+i) for i in range(4)}
    {0 : 'A', 1 : 'B', 2 : 'C', 3 : 'D'}

List1 = ['This', 'is', 'a', 'list']
List2 = ['Put', 'this', 'into', 'dictionary']

d = {List1[n]: List2[n] for n in range(len(List1))}