Practice Problem

Instructions

Writing class, methods, and functions

1. Write a PlaneTicket class with attributes: departure_city: str, arrival_city: str, departure_time: int, ticket_cost: float.
2. Write an __init__ magic method that takes city_a: str, city_b: str, depart: int, and cost: float as arguments as creates a new PlaneTicket with the attributes departure_city = city_a, arrival_city = city_b, departure_time = depart, and ticket_cost = cost.
3. Write a __str__ magic method to print out ticket info. (Format however you want.)
4. Write a delay method that takes delay_hours: int as an argument and increases the departure_time by that much. (Think of time like military time… 1 am is 0100, 1 pm is 1300, etc.)
5. Write a discount method that takes a discount: float as an argument and discounts ticket_cost by that percent. (E.g. if discount = .15, then discount ticket_cost by 15%)
6. Write a find_cheapest_ticket function that takes as input a list of PlaneTickets and returns the PlaneTicket with the lowest cost.

Writing code to instantiate class and test methods and functions

1. Create a PlaneTicket object that starts in “Raleigh” and ends in “New Orleans”. It departs at 10 am (1000) and costs $85.25.
2. Print out the ticket info.
3. Delay the flight by 2 hours.
4. Discount it by 10%.
5. Create another PlaneTicket object that starts in “Orlando” and ends in “San Fransisco”. It departs at 11 am (1100) and costs $100.50.
6. Print out the which ticket is cheaper using the find_cheapest_ticket function.

Solution

    class PlaneTicket:
        
        departure_city: str
        arrival_city: str
        departure_time: int
        ticket_cost: float
        
        def __init__(self, city_a: str, city_b: str, depart: int, cost: float):
            """Initialize PlaneTicket Class"""
            self.departure_city = city_a
            self.arrival_city = city_b
            self.departure_time = depart
            self.ticket_cost = cost
            
        def __str__(self) -> str:
            """Visualize my ticket"""
            my_ticket_str: str = f"Depart from {self.departure_city} at {self.departure_time}. "
            my_ticket_str += f"Arrive at {self.arrival_city}. It costs ${round(self.ticket_cost, 2)}."
            return my_ticket_str 
        
        def delay(self, delay_hours: int) -> None:
            """Delay departure_time by delay_hours"""
            self.departure_time += (delay_hours * 100)
            self.departure_time %= 2400
        
        def discount(self, discount: float) -> None:
            """Discount ticket_cost by 'discount'"""
            #If discounting by .15, then multiply by (1-.15) 
            self.ticket_cost = self.ticket_cost * (1 - discount)
            
    def find_cheapest_ticket(tickets: list[PlaneTicket]) -> PlaneTicket:
        min_ticket: PlaneTicket = tickets[0]
        for t in tickets:
            if t.ticket_cost < min_ticket.ticket_cost:
                min_ticket = t
        return min_ticket
            

    my_ticket: PlaneTicket = PlaneTicket("Raleigh", "New Orleans", 1000, 85.25)

    print(my_ticket)

    my_ticket.delay(2)
    my_ticket.discount(.10)

    other_ticket: PlaneTicket = PlaneTicket("Orlando", "San Fransisco", 1100, 100.50)

    print(find_cheapest_ticket([my_ticket, other_ticket]))