John Smith
John Smith

Reputation: 115

Python sort a JSON list by two key values

I have a JSON list looks like this:

[{ "id": "1", "score": "100" },
{ "id": "3", "score": "89" },
{ "id": "1", "score": "99" },
{ "id": "2", "score": "100" },
{ "id": "2", "score": "59" }, 
{ "id": "3", "score": "22" }]

I want to sort the id first, I used

sorted_list = sorted(json_list, key=lambda k: int(k['id']), reverse = False)

This will only sort the list by id, but base on id, I also want sort the score as will, the final list I want is like this:

[{ "id": "1", "score": "100" },
{ "id": "1", "score": "99" },
{ "id": "2", "score": "100" },
{ "id": "2", "score": "59" },
{ "id": "3", "score": "89" }, 
{ "id": "3", "score": "22" }]

So for each id, sort their score as well. Any idea how to do that?

Upvotes: 3

Views: 8664

Answers (1)

Padraic Cunningham
Padraic Cunningham

Reputation: 180401

use a tuple adding second sort key -int(k["score"]) to reverse the order when breaking ties and remove reverse=True:

sorted_list = sorted(json_list, key=lambda k: (int(k['id']),-int(k["score"])))

[{'score': '100', 'id': '1'}, 
 {'score': '99', 'id': '1'}, 
 {'score': '100', 'id': '2'}, 
 {'score': '59', 'id': '2'},
 {'score': '89', 'id': '3'}, 
 {'score': '22', 'id': '3'}]

So we primarily sort by id from lowest-highest but we break ties using score from highest-lowest. dicts are also unordered so there is no way to put id before score when you print without maybe using an OrderedDict.

Or use pprint:

from pprint import pprint as pp

pp(sorted_list)

[{'id': '1', 'score': '100'},
 {'id': '1', 'score': '99'},
 {'id': '2', 'score': '100'},
 {'id': '2', 'score': '59'},
 {'id': '3', 'score': '89'},
 {'id': '3', 'score': '22'}]

Upvotes: 6

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