Convert a list of dictionaries to a dictionary

Question

I have a list of dictionaries in Python

[
{'id':'1', 'name': 'a', 'year': '1990'},
{'id':'2', 'name': 'b', 'year': '1991'},
{'id':'3', 'name': 'c', 'year': '1992'},
{'id':'4', 'name': 'd', 'year': '1993'},
]

I want to turn this list into a dictionary of dictionaries with the key being the value of name. Note here different items in the list have different values of name.

{
'a': {'id':'1', 'year': '1990'},
'b': {'id':'2', 'year': '1990'},
'c': {'id':'3', 'year': '1990'},
'd': {'id':'4', 'year': '1990'}
}

What is the best way to achieve this? Thanks.

This is similar to Python - create dictionary from list of dictionaries, but different.

Have you tried anything? – Ashwini Chaudhary Apr 03 '15 at 12:34 — Ashwini Chaudhary, Apr 03 '15 at 12:34

score 13 · Answer 1 · edited May 23 '17 at 12:30

You can also achieve this using Dictionary Comprehension.

data = [
        {'id':'1', 'name': 'a', 'year': '1990'},
        {'id':'2', 'name': 'b', 'year': '1991'},
        {'id':'3', 'name': 'c', 'year': '1992'},
        {'id':'4', 'name': 'd', 'year': '1993'},
       ]

print {each.pop('name'): each for each in data}

Results :-

{'a': {'year': '1990', 'id': '1'}, 
 'c': {'year': '1992', 'id': '3'}, 
 'b': {'year': '1991', 'id': '2'}, 
 'd': {'year': '1993', 'id': '4'}}

score 3 · Answer 2 · answered Apr 03 '15 at 12:38

3

def to_dict(dicts):
    if not dicts:
        return {}
    out_dict = {}
    for d in dicts:
        out_dict[d.pop('name')] = d
    return out_dict

answered Apr 03 '15 at 12:38

Łukasz Rogalski

22,092
8
59
93

1

You don't need the guard clause (`if not dicts: return {}`). If `dicts` is empty, `return out_dict` will return an empty dictionary anyway. (Also, thanks for reminding me that dictionaries have a `pop` method.) – Kevin J. Chase Apr 03 '15 at 12:51
2

I want to return dict even if `None` is passed as a argument value. – Łukasz Rogalski Apr 03 '15 at 12:53
Gotcha. Matter of taste to you handle a `None` input, I guess. – Kevin J. Chase Apr 03 '15 at 13:17

no_name · Answer 3 · 2015-04-03T12:39:21.250

1

z = [
{'id':'1', 'name': 'a', 'year': '1990'},
{'id':'2', 'name': 'b', 'year': '1991'},
{'id':'3', 'name': 'c', 'year': '1992'},
{'id':'4', 'name': 'd', 'year': '1993'},
]
dict_ = {indic['name']:{
        k:indic[k] for k in indic if k != 'name'} for indic in z}

edited Apr 03 '15 at 12:39

answered Apr 03 '15 at 12:36

no_name

742
3
10

Thanks. Can it be created so that no need to specify other keys like `'id':x['id'], 'year':x['year']` ? – Tim Apr 03 '15 at 12:37

score 1 · Answer 4 · answered Apr 03 '15 at 12:39

try like this:

>>> my_list = [
{'id':'1', 'name': 'a', 'year': '1990'},
{'id':'2', 'name': 'b', 'year': '1991'},
{'id':'3', 'name': 'c', 'year': '1992'},
{'id':'4', 'name': 'd', 'year': '1993'},
]
>>> my_dict = {}
>>> for x in my_list:
...     my_dict[x['name']] = dict((key, value) for key,value in x.items() if key!='name')
... 
>>> my_dict
{'a': {'id': '1', 'year': '1990'}, 'c': {'id': '3', 'year': '1992'}, 'b': {'id': '2', 'year': '1991'}, 'd': {'id': '4', 'year': '1993'}}

Convert a list of dictionaries to a dictionary

4 Answers4