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Somme des valeurs dans une liste de listes de dictionnaires utilisant des paires clé-valeur communes

Comment additionner les éléments en double dans une liste de listes de dictionnaires?

Exemple de liste:

data = [
        [
            {'user': 1, 'rating': 0},
            {'user': 2, 'rating': 10},
            {'user': 1, 'rating': 20},
            {'user': 3, 'rating': 10}
        ],
        [
            {'user': 4, 'rating': 4},
            {'user': 2, 'rating': 80},
            {'user': 1, 'rating': 20},
            {'user': 1, 'rating': 10}
        ],
    ]

Production attendue:

op = [
        [
            {'user': 1, 'rating': 20},
            {'user': 2, 'rating': 10},
            {'user': 3, 'rating': 10}
        ],
        [
            {'user': 4, 'rating': 4},
            {'user': 2, 'rating': 80},
            {'user': 1, 'rating': 30},
        ],
    ]
pythondictionarynested-lists
10
c.grey
op = []
for lst in data:
    rating_of_user = {}
    for e in lst:
        user, rating = e['user'], e['rating']
        rating_of_user[user] = rating_of_user.get(user, 0) + rating
    op.append([{'user': u, 'rating': r} for u, r in rating_of_user.items()])

N.B .: puisque Python 3.7 les dictionnaires conservent officiellement l'ordre d'insertion

2
Walter Tross

Cela devrait fonctionner:

from collections import defaultdict

data_without_duplicates = []
for l in data:
    users_ratings = defaultdict(int)
    for d in l:
        users_ratings[d["user"]] += d["rating"]
    data_without_duplicates.append(
        [{"user": user, "rating": rating} for user, rating in users_ratings.items()]
    )
1
Edison Feneyab

Compréhension de liste Python:

from collections import Counter
x = [[
        {'user': x[0], 'rating': x[1]} for x in
        Counter({d['user']: d['rating'] for d in group}).most_common()] for group in data
]

Production:

[
    [
        {
            "rating": 20, 
            "user": 1
        }, 
        {
            "rating": 10, 
            "user": 2
        }, 
        {
            "rating": 10, 
            "user": 3
        }
    ], 
    [
        {
            "rating": 80, 
            "user": 2
        }, 
        {
            "rating": 10, 
            "user": 1
        }, 
        {
            "rating": 4, 
            "user": 4
        }
    ]
]
0
Maurice Meyer
data = [
        [
            {'user': 1, 'rating': 0},
            {'user': 2, 'rating': 10},
            {'user': 1, 'rating': 20},
            {'user': 3, 'rating': 10}
        ],
        [
            {'user': 4, 'rating': 4},
            {'user': 2, 'rating': 80},
            {'user': 1, 'rating': 20},
            {'user': 1, 'rating': 10}
        ],
    ]


keyname = "user"

all = []
for row in data:
    row_out = []
    for d in row:
        key = d[keyname]
        for d2 in row_out:
            if d2[keyname] == d[keyname]:
                break
        else:
            d2 = {keyname: key}
            row_out.append(d2)
        for k, v in d.items():
            if k == keyname:
                continue
            d2[k] = d2.get(k, 0) + v
    all.append(row_out)

print(all)

donne:

[[{'user': 1, 'rating': 20}, {'user': 2, 'rating': 10}, {'user': 3, 'rating': 10}], [{'user': 4, 'rating': 4}, {'user': 2, 'rating': 80}, {'user': 1, 'rating': 30}]]
0
alaniwi

Le tri doit être évité car chaque élément peut être traité en un seul passage. Toute technique basée sur le hachage devrait être meilleure.

Voici une solution alternative, qui utilise un defaultdict au lieu de coûteux sort/groupby ou pandas.

from collections import defaultdict
from functools import reduce

def reduce_func(state, item):
  new_obj = {
    "user": item["user"],
    "rating": state[item["user"]]["rating"] + item["rating"]}
  }
  state[item["user"]] = new_obj
  return state

output = [list(reduce(reduce_func, elem, defaultdict(lambda: {"rating": 0})).values())
          for elem in data]
0
UltraInstinct
import pprint
data = [
        [
            {'user': 1, 'rating': 0},
            {'user': 2, 'rating': 10},
            {'user': 1, 'rating': 20},
            {'user': 3, 'rating': 10}
        ],
        [
            {'user': 4, 'rating': 4},
            {'user': 2, 'rating': 80},
            {'user': 1, 'rating': 20},
            {'user': 1, 'rating': 10}
        ],
    ]

def find(user, l):
    for i, d in enumerate(l):
        if user == d['user']:
            return i
    return -1

data_sum = []

for l in data:
    list_sum = []
    for d in l:
        idx = find(d['user'], list_sum)
        if idx == -1:
            list_sum.append(d)
        else:
            list_sum[idx]['rating'] += d['rating']
    data_sum.append(list_sum)

pprint.pprint(data_sum)
0
mangupt