CODEWITHSUNDEEP
pythonpython-2.7
Alpesh Valaki
Alpesh Valaki

Reputation: 1631

Find duplicate from list and sum

data = [(0, 0, {'product_id': 6, 'qty': 1.0}), (0, 0, {'product_id': 8, 'qty': 1.0}), (0, 0, {'product_id': 7, 'qty': 2.0}), (0, 0, {'product_id': 6, 'qty': 1.0}), (0, 0, {'product_id': 8, 'qty': 1.0}), (0, 0, {'product_id': 7, 'qty': 2.0})]

I have this list, What i want to do is to find repeted product id and sum theire qty and remove duplicate product id elelment from list

Output of list should be:

 new_data = [(0, 0, {'product_id': 6, 'qty': 2.0}), (0, 0, {'product_id': 8, 'qty': 2.0}), (0, 0, {'product_id': 7, 'qty': 4.0})]

Upvotes: 0

Views: 164

Answers (2)

Alireza Afzal Aghaei
Alireza Afzal Aghaei

Reputation: 1235

one line solution:

data = [(0, 0, {'product_id': 6, 'qty': 1.0}), (0, 0, {'product_id': 8, 'qty': 1.0}),
        (0, 0, {'product_id': 7, 'qty': 2.0}), (0, 0, {'product_id': 6, 'qty': 1.0}),
        (0, 0, {'product_id': 8, 'qty': 1.0}), (0, 0, {'product_id': 7, 'qty': 2.0})]

import itertools
import functools
from operator import itemgetter

[functools.reduce(lambda x, y: (x[0], x[1], {'product_id': x[2]['product_id'], 'qty': x[2]['qty'] + y[2]['qty']}), y) for _,y in itertools.groupby(sorted(data, key=lambda x: itemgetter('product_id')(itemgetter(2)(x))),key=lambda x: itemgetter('product_id')(itemgetter(2)(x)))]

Upvotes: 1

Josh Parnell
Josh Parnell

Reputation: 1216

I think the simplest way is to build a dictionary (map) for your product ids, extract your data into that dictionary, then build your new data list. Example:

from collections import defaultdict
def mergeQty(data):
  qtyMap = defaultdict(float)
  for x, y, product in data:
    id = product['product_id']
    qty = product['qty']
    qtyMap[(x, y, id)] += qty

  return [(x, y, { 'product_id' : id, 'qty' : qty }) for (x, y, id), qty in qtyMap.iteritems()]

Note that this will not merge products whose first two values differ (in your example they are all 0's, and we can only guess at what those mean).

EDIT: Thanks Azat for defaultdict suggestion.

EDIT: Keeping unknown fields x and y intact as per kuro's suggestion.

Upvotes: 3

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