Data processing List of dict without using libraries or import

Question

I’m studying data processing in python with apply Count, Sum, Group, Sort on a list of dict

list_data = [
              {"name": "milk", "quantity": 1, "price_of_one": 2000},
              {"name": "egg", "quantity": 12, "price_of_one": 500},
              {"name": "egg", "quantity": 6, "price_of_one": 500},
              {"name": "milk", "quantity": 2, "price_of_one": 2000},
              {"name": "meat", "quantity": 1, "price_of_one": 10000}
            ]

I want to handle this list with the expected result:

list_data = [
              {"name": "egg", "quantity": 18, "total": 9000, "number_occurrences": 2},
              {"name": "milk", "quantity": 3, "total": 6000, "number_occurrences": 2},
              {"name": "meat", "quantity": 1, "total": 10000, "number_occurrences": 1}
            ]

As seen, I need SUM by "quantity", SUM by "quantity*price_of_one", GROUP by "name", SORT by SUM of quantity and COUNT number occurrences.

I don’t know How do I make it right?. Is there any way I can get the expected result?

Asked By: Alain Skyter

||

Source

Answer 1

You can use dict.setdefault/dict.get:

out = {}
for d in list_data:
    d2 = out.setdefault(d['name'], {'name': d['name']})
    d2['quantity'] = d2.get('quantity', 0) + d['quantity']
    d2['total'] = d2.get('total', 0) + d['quantity']*d['price_of_one']
    d2['number_occurrences'] = d2.get('number_occurrences', 0)+1

out = list(out.values())

output:

[{'name': 'milk', 'quantity': 3, 'total': 6000, 'number_occurrences': 2},
 {'name': 'egg', 'quantity': 18, 'total': 9000, 'number_occurrences': 2},
 {'name': 'meat', 'quantity': 1, 'total': 10000, 'number_occurrences': 1},
]

sorted output:

out = sorted(out, key=lambda x: (x['quantity'], x['number_occurrences']),
             reverse=True)

output:

[{'name': 'egg', 'quantity': 18, 'total': 9000, 'number_occurrences': 2},
 {'name': 'milk', 'quantity': 3, 'total': 6000, 'number_occurrences': 2},
 {'name': 'meat', 'quantity': 1, 'total': 10000, 'number_occurrences': 1}]

Answered By: mozway

Data processing List of dict without using libraries or import

Question:

Answers:

sorted output: