CODEWITHSUNDEEP
djangodjango-rest-framework
kaysiz
kaysiz

Reputation: 60

How to create a list of objects by grouping them by a common name

i have a list of ungrouped objects and i want to return a list of grouped objects by a common value

[{"name": "test", "group": "A"},{"name": "test2", "group": "B"},{"name": "test3", "group": "A"},{"name": "test4", "group": "B"}]

I want to return this

[{"group":"A","users":[{"name":"test"},{"name":"test3"}]}]

Upvotes: 1

Views: 60

Answers (2)

Paul Whipp
Paul Whipp

Reputation: 16531

While Willem's answer is correct for the OP's question as asked, it is more common to want the grouping 'by' the common value and thus to want to obtain a mapping rather than a list thus:

from collections import defaultdict

users = [
    {"name": "test", "group": "A"},
    {"name": "test2", "group": "B"},
    {"name": "test3", "group": "A"},
    {"name": "test4", "group": "B"}]

users_by_group = defaultdict(list)

for user in users:
    users_by_group[user['group']].append(user)


#users_by_group:
#  A:
#  - group: A
#    name: test
#  - group: A
#    name: test3
#  B:
#  - group: B
#    name: test2
#  - group: B
#    name: test4

Upvotes: 1

willeM_ Van Onsem
willeM_ Van Onsem

Reputation: 476719

You can use groupby of itertools:

from itertools import groupby
from operator import itemgetter

result = [
    { 'group': g, 'users': [{'name': v['name']} for v in vs] }
    for k, vs in groupby(sorted(mylist, itemgetter('group')), itemgetter('group'))
]

Upvotes: 1

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