在字典的字典中更新特定字典的键

Question

I'm creating a dictionary of dictionaries and then trying to update a specific key using for loop. however, all keys are getting updated.

code is as follows:

transactions = Transaction.objects.all()

unique_sellers = ['A002638841D', 'A09876543456']
seller_summary={}
summary = {
        'total_loan_amount': 0,
        'gross_incentive': 0,
        }

for each in unique_sellers:
    seller_summary[each] = summary
    seller_summary[each]['total_loan_amount'] = transactions.filter(channel_seller__pin_no = each).aggregate(total_loan_amount=Sum('loan_amount'))['total_loan_amount']

print(seller_summary)

total_loan_amount for A002638841D is 1500

total_loan_amount for A09876543456 is 2000

my expectations is output of print(seller_summary) should be {'A002638841D': {'total_loan_amount': 1500, 'gross_incentive': 0,}, 'A09876543456': { 'total_loan_amount': 2000, 'gross_incentive': 0,}}

However, I'm getting output as follows my expectations is output of {'A002638841D': {'total_loan_amount': 2000, 'gross_incentive': 0,}, 'A09876543456': { 'total_loan_amount': 2000, 'gross_incentive': 0,}}

total_loan_amount is both the dict is getting updated as 2000 instead of 1500 and 2000 respectively

Answer 1

When you assign the summary dict for each key, summary is a reference of the original summary variable, so you update twice the same dict. Maybe you could try

transactions = Transaction.objects.all()

unique_sellers = ['A002638841D', 'A09876543456']
seller_summary={}
def get_summary(): # create a new reference each time instead of using the same one
    return {
        'total_loan_amount': 0,
        'gross_incentive': 0,
    }

for each in unique_sellers:
    seller_summary[each] = get_summary()
    # EDIT: Or like said in comments, simply create the dict reference here :
    # seller_summary[each] = {  'total_loan_amount': 0, 'gross_incentive': 0,}
    seller_summary[each]['total_loan_amount'] = transactions.filter(channel_seller__pin_no = each).aggregate(total_loan_amount=Sum('loan_amount'))['total_loan_amount']

print(seller_summary)