从词典列表中创建词典子集

Question

I have a list of dictionaries that looks like the following:

d = [{'first':'jason','color':'green','age':22},
     {'first':'josh','color':'red','age':22},
     {'first':'chris','color':'blue','age':21}
    ]

I want to create a dictionary that is a subset of the previous dictionaries.

Something that looks like:

newD = {'jason':22, 'josh':22, 'chris':21}

The following does the trick:

first = [k['first'] for k in d]
age = [k['age'] for k in d]
newD = dict(zip(first, age))

But is there a more Pythonic/cleaner way to do this?

Answer 1

newd = {dd['first']: dd['age'] for dd in d}

Output:

In [3]: newd
Out[3]: {'chris': 21, 'jason': 22, 'josh': 22}

Answer 2

Yes, you only need one comprehension:

>>> {x['first']: x['age'] for x in d}
{'jason': 22, 'josh': 22, 'chris': 21}

Answer 3

也许这个？

newD = dict((x['first'], x['age']) for x in d)

Answer 4

Using operator.itemgetter :

from operator import itemgetter

res = dict(map(itemgetter('first', 'age'), d))

{'jason': 22, 'josh': 22, 'chris': 21}