Lists Of Class Objects

A class may have a property that is list and contains class instances.

Example

class Car:
    def __init__(self, model, price):
        self.model = model
        self.price = price
    
    def printData(self):
        print("Model:", self.model)
        print("Price:", self.price)
    
class CarDealership:
    def __init__(self):
        self.cars = []
    
    def sortByPrice(self):
        # sort cars by price:
        self.cars.sort(key=lambda x: x.price)
    
    def listCarsData(self):
        for car in self.cars:
            print("--------")l
            car.printData()
    
carDealership = CarDealership()
    
car_1 = Car("Ford Fiesta", 20000)
car_2 = Car("Toyota Corolla", 26000)
car_3 = Car("Renault Clio", 18000)
    
carDealership.cars = []
    
# Add elements to the list:
carDealership.cars.append(car_1)
carDealership.cars.append(car_2)
carDealership.cars.append(car_3)
    
print("Before Sorting:")
print('')
    
carDealership.listCarsData()
    
carDealership.sortByPrice()
print('')
print("After Sorting:")
print('')
    
carDealership.listCarsData()

Output:

Explanation:

At line 12 an empty list is created.
At lines 32 - 34 elements are added to the list.
At line 16 the list is sorted ascending by price. If we replace line 16 with self.cars.sort(key=lambda x: x.price, reverse=True), then the sorting would be descending.