sort_operator.py

import operator


class Item:
    def __init__(self, name, price, qty):
        self.name = name
        self.price = price
        self.qty = qty

    def total_cost(self):
        return self.price * self.qty

    def __repr__(self):
        return f'({self.name} ${self.price} x {self.qty} = ${self.total_cost()})'


items = [
    Item("iPhone", 999, 5),
    Item("iMac", 2999, 2),
    Item("iPad", 599, 11)
]


def print_items(title, item_list):
    print(title)
    print(*item_list, sep=', ', end='\n\n')


print_items('Original:', items)

items_by_price = sorted(items, key=operator.attrgetter('price'))
print_items('Sorted by price:', items_by_price)

items_by_total_cost = sorted(items, key=operator.methodcaller('total_cost'))
print_items('Sorted by total cost:', items_by_total_cost)

"""
Original:
(iPhone $999 x 5 = $4995), (iMac $2999 x 2 = $5998), (iPad $599 x 11 = $6589)

Sorted by price:
(iPad $599 x 11 = $6589), (iPhone $999 x 5 = $4995), (iMac $2999 x 2 = $5998)

Sorted by total cost:
(iPhone $999 x 5 = $4995), (iMac $2999 x 2 = $5998), (iPad $599 x 11 = $6589)
"""