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Python

Posted by Gideon De Villiers
Gideon De Villiers
Courses Plus Student 632 Points

Dealing with multiple ValueErrors

TICKET_PRICE = 10
tickets_remaining = 100

while tickets_remaining >= 1:
    print("There are {} tickets remaining.  ".format(tickets_remaining))
    name = input("What is your name?  ")
    ticket_request = input("Hi {}, how many tickets would you like to purchase?  ".format(name))
    #expect value error if non int. 
    try:
        ticket_request = int(ticket_request)
        if ticket_request > tickets_remaining:
            raise ValueError("There are only {} tickets remaining. Nice try!.".format(tickets_remaining))
    except ValueError as err:
        print("Oh no we ran into an issue. {} Please try again.".format(err))
    else:
        price = TICKET_PRICE * int(ticket_request)
        print("Okay {}, that will be ${}.".format(name, price))
        proceed = input("Would you like to proceed Y/N?  ")
        if proceed.lower() == "y":
            print("Sold!  ")
    # TODO: Gather credit card information. 
            tickets_remaining -= ticket_request      
        else:
            print("Okay {}, thanks anyway!  ".format(name))
print("Sorry, we are sold out! ")

This code works fine unless the user enters a non-integer as in input for ticket_request. It returns:

Oh no we ran into an issue. invalid literal for int() with base 10: 'si' Please try again.

I'd like to make this return more user-friendly. Any advice?

Gideon De Villiers
Gideon De Villiers
Courses Plus Student 632 Points 
TICKET_PRICE = 10
tickets_remaining = 100

while tickets_remaining >= 1:
    print("There are {} tickets remaining.  ".format(tickets_remaining))
    name = input("What is your name?  ")
    ticket_request = input("Hi {}, how many tickets would you like to purchase?  ".format(name))
    try:

#solution

        if not ticket_request.isdigit():
            raise ValueError(" Please enter a number using the keypad.")

#end solution

        ticket_request = int(ticket_request)
        if ticket_request > tickets_remaining:
            raise ValueError("There are only {} tickets remaining. Nice try!.".format(tickets_remaining))
    except ValueError as err:
        print("Oh no we ran into an issue. {} Please try again.".format(err))
    else:
        price = TICKET_PRICE * int(ticket_request)
        print("Okay {}, that will be ${}.".format(name, price))
        proceed = input("Would you like to proceed Y/N?  ")
        if proceed.lower() == "y":
            print("Sold!  ")
    # TODO: Gather credit card information. 
            tickets_remaining -= ticket_request      
        else:
            print("Okay {}, thanks anyway!  ".format(name))
print("Sorry, we are sold out! ")