字典的分组和总和列表(按参数) [英] Group and sum list of dictionaries by parameter

问题描述

我有我的产品(饮料，食品等)的词典列表，有些产品可能要添加几次.我需要按product_id参数对我的产品进行分组，然后将每个组的product_cost和product_quantity相加，以得出总产品价格.

I have a list of dictionaries of my products (drinks, food, etc), some of the products may be added several times. I need to group my products by product_id parameter and sum product_cost and product_quantity of each group to get the total product price.

我是python的新手，了解如何对字典列表进行分组，但无法弄清楚如何对某些参数值求和.

I'm a newbie in python, understand how to group list of dictionaries but can't figure out how to sum some parameter values.

"products_list": [
    {
        "product_cost": 25,
        "product_id": 1,
        "product_name": "Coca-cola",
        "product_quantity": 14,
    },
    {
        "product_cost": 176.74,
        "product_id": 2,
        "product_name": "Apples",
        "product_quantity": 800,

    },
    {
        "product_cost": 13,
        "product_id": 1,
        "product_name": "Coca-cola",
        "product_quantity": 7,
    }
]

我需要实现以下目标:

"products_list": [
    {
        "product_cost": 38,
        "product_id": 1,
        "product_name": "Coca-cola",
        "product_quantity": 21,
    },
    {
        "product_cost": 176.74,
        "product_id": 2,
        "product_name": "Apples",
        "product_quantity": 800,

    }
]

推荐答案

您可以首先对product_name上的词典列表进行排序，然后根据product_name

You can start by sorting the list of dictionaries on product_name, and then group items based on product_name

然后为每个组计算总产品和总数量，创建最终字典并更新到列表，然后创建最终字典

Then for each group, calculate the total product and total quantity, create your final dictionary and update to the list, and then make your final dictionary

from itertools import groupby

dct = {"products_list": [
    {
        "product_cost": 25,
        "product_id": 1,
        "product_name": "Coca-cola",
        "product_quantity": 14,
    },
    {
        "product_cost": 176.74,
        "product_id": 2,
        "product_name": "Apples",
        "product_quantity": 800,

    },
    {
        "product_cost": 13,
        "product_id": 1,
        "product_name": "Coca-cola",
        "product_quantity": 7,
    }
]}

result = {}
li = []

#Sort product list on product_name
sorted_prod_list = sorted(dct['products_list'], key=lambda x:x['product_name'])

#Group on product_name
for model, group in groupby(sorted_prod_list,key=lambda x:x['product_name']):

    grp = list(group)

    #Compute total cost and qty, make the dictionary and add to list
    total_cost = sum(item['product_cost'] for item in grp)
    total_qty = sum(item['product_quantity'] for item in grp)
    product_name = grp[0]['product_name']
    product_id = grp[0]['product_id']

    li.append({'product_name': product_name, 'product_id': product_id, 'product_cost': total_cost, 'product_quantity': total_qty})

#Make final dictionary
result['products_list'] = li

print(result)

输出将是

{
    'products_list': [{
            'product_name': 'Apples',
            'product_id': 2,
            'product_cost': 176.74,
            'product_quantity': 800
        },
        {
            'product_name': 'Coca-cola',
            'product_id': 1,
            'product_cost': 38,
            'product_quantity': 21
        }
    ]
}

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