Extract values from list with dicts

June 21, 2023

I have a list with orders. Each order contains products and their prices.
What I want is to write the shortest script possible to count total number of products sold and total amount of money earned. I’m looking for fields "count" and "total".

[
   {
      "id":1,
      "items":[
         {
            "offerName":"name_1",
            "count":6,
            "prices":[
               {
                  "costPerItem":129.0,
                  "total":774.0
               }
            ]
         },
         {
            "offerName":"name_2",
            "count":1,
            "prices":[
               {
                  "costPerItem":120.0,
                  "total":120.0
               }
            ]
         }
      ]
   },
   {
      "id":2,
      "items":[
         {
            "offerName":"name_3",
            "count":10,
            "prices":[
               {
                  "costPerItem":30.0,
                  "total":300.0
               }
            ]
         },
         {
            "offerName":"name_4",
            "count":1,
            "prices":[
               {
                  "costPerItem":10.0,
                  "total":10.0
               }
            ]
         }
      ]
   }
]

I got the right values, but I think there is a way to make the calculation more beautiful, without a lot of looping.

counts = []
prices = []
for order in sales_data:
    products_list = order.get("items", [])
    for offer in products_list:
        counts.append(offer.get("count", 0))
        prices.append(offer.get("prices", []))
total_earned=[]
for price in prices:
    total = price[0].get("total", 0)
    total_earned.append(total)

print(sum(counts))
print(sum(total_earned))

>Solution :

For making the code as brief as possible, list comprehensions can be used.

I have come up with a solution with only 2 lines of logic.

I have defined the initial count and price as zero, and using list comprehension, I am updating the count and price for each item every iteration using the assignment operator :=

sales_data = [
    {
        "id": 1,
        "items": [
            {
                "offerName": "name_1",
                "count": 6,
                "prices": [
                    {
                        "costPerItem": 129,
                        "total": 774
                    }
                ]
            },
            {
                "offerName": "name_2",
                "count": 1,
                "prices": [
                    {
                        "costPerItem": 120,
                        "total": 120
                    }
                ]
            }
        ]
    },
    {
        "id": 2,
        "items": [
            {
                "offerName": "name_3",
                "count": 10,
                "prices": [
                    {
                        "costPerItem": 30,
                        "total": 300
                    }
                ]
            },
            {
                "offerName": "name_4",
                "count": 1,
                "prices": [
                    {
                        "costPerItem": 10,
                        "total": 10
                    }
                ]
            }
        ]
    }
]


count, prices = 0, 0
[(count:=count+item['count'], prices:=prices+item['prices'][0]['total']) for sale in sales_data for item in sale['items']]

print('Count:', count, ', Prices:', prices)

This code outputs