CODEWITHSUNDEEP
pythondjangomodelcurrency
darren
darren

Reputation: 19399

Work out correct money denominations for change

Working on a django project. On my payment model I have a simple def save

def save(self, *args, **kwargs):
    self.amount_change = self.amount_due - self.amount_paid
    return super(Payment, self).save(*args, **kwargs)

If my amount_change comes to -455.50 I'd like to return change as

What I'd like to do is breakdown the amount_change into the money denominations that I have and return the change to the client with the correct notes and or coins. My denominations are [200, 100, 50, 20, 10, 5, 1, 0.5]

How do I go about doing this? Any help is appreciated.

Upvotes: 0

Views: 3615

Answers (1)

Scott Woodall
Scott Woodall

Reputation: 10676

Building upon this answer, I believe this is returning the desired results:

from collections import Counter

def change(amount):
    money = ()

    for coin in [200, 100, 50, 20, 10, 5, 1, 0.5]:
        num = int(amount/coin)
        money += (coin,) * num
        amount -= coin * num

    return Counter(money)

Input and output:

>>> c = change(455.50)
>>> print c
Counter({200: 2, 0.5: 1, 50: 1, 5: 1})

Edit: If you need to pass in a negative number, create a new variable inside the function by multiplying by -1 and use it inside the function instead of amount

Upvotes: 1

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