Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Python Python Basics All Together Now Handle Exceptions

Posted by Allen Hoessli
Allen Hoessli
496 Points

Negative entry

I was testing this code. Instead of going to 10000 to catch a ValueError, I typed -10. When I completed the transaction, it added 10 to the total. In a real life situation, we probably wouldn't want that problem. How could we remedy that?

Nicolás Melgarejo
Nicolás Melgarejo
15,586 Points
Nicolás Melgarejo
Nicolás Melgarejo
15,586 Points

I use this:

number_of_tickets = input("How many tickets do you like {}?   ".format(user_name))
    # Expect a ValueError
    try:
        number_of_tickets = int(number_of_tickets)
        if number_of_tickets > tickets_remaining:
            raise ValueError("The number of tickets that you want to buy exeed de number of tickets remaining ({}).".format(tickets_remaining))
        elif number_of_tickets <= 0:
            raise ValueError("More than 0 tickets are require.")
    except ValueError as err:
        print("Oh no, we ran into a issue. Please try again")
        print("{}".format(err))

1 Answer

Steven Parker
Steven Parker
231,521 Points
Steven Parker
Steven Parker
231,521 Points

The easiest solution might be to have another test, such as if num_tickets <= 0. If that condition is true, you could raise a ValueError with a message like "your entry must be a positive number".