"Invalid literal" when entering a character into a int question

Hi Asher Orr , I came across a similar problem with the code below:

    tickets = input(f"How many tickets would you like to purchase, {first_name}? ")

    try: 
        tickets = int(tickets)
        if tickets > tickets_remaining:
            raise ValueError(f"Sorry, we don't have that many tickets left. There are only {tickets_remaining} left available.")
    except ValueError as err:
        print(f"It looks like we've come across an error. {err} Please try again.")

when I try to to give an input of "hi" (for example) when prompted "How many tickets...", I get It looks like we've come across an error. invalid literal for int() with base 10: 'hi' Please try again.

I originally had my code as

    tickets = input(f"How many tickets would you like to purchase, {first_name}? ")

    try: 
        tickets = int(tickets)
        if tickets > tickets_remaining:
            raise ValueError(f"Sorry, we don't have that many tickets left. There are only {tickets_remaining} left available.")
    except ValueError as err:
        print(err)
        print(f"It looks like we've come across an error. Please try again.")

And it came with the same issue just laid out differently so I watched the video... then we're never shown another run where a string's inputted in that prompt.

Is it really meant to come out that way? I looked back on the video and they did the same with the "tickets" variable...

edit: Oh. Okay, I think I get it. Is it because I need to do another except block, but this time for a TypeError?

edit 2: Okay that seemed to work when I did this:

    tickets = input(f"How many tickets would you like to purchase, {first_name}? ")

    try: 
        tickets = tickets
        if tickets > tickets_remaining:
            raise ValueError(f"Sorry, we don't have that many tickets left. There are only {tickets_remaining} left available.")
    except ValueError as err:
        print(err)
        print(f"It looks like we've come across an error. Please try again.")
    except TypeError:
        print("Please try again and make sure to input a whole number.") 

My question is though, is there a more concise way of doing this 😬 Unless I'm getting ahead of myself and this is going to be covered in the next video

Hi Tricia Cruz, great question.

You should check out this post on StackOverflow.

A Value error is raised when a built-in operation or function receives an argument that has the right type but an inappropriate value.

On the other hand, passing arguments of the wrong type (e.g. passing a list when an int is expected) should result in a TypeError.

  tickets = input(f"How many tickets would you like to purchase, {first_name}? ")

    try: 
        tickets = tickets
        if tickets > tickets_remaining:
            raise ValueError(f"Sorry, we don't have that many tickets left. There are only {tickets_remaining} left available.")
    except ValueError as err:
        print(err)
        print(f"It looks like we've come across an error. Please try again.")
    except TypeError:
        print("Please try again and make sure to input a whole number.") 

I put the code above into my IDE, and I got a TypeError no matter what I entered. It's because of these lines:

 try: 
        tickets = tickets
        if tickets > tickets_remaining:

The second line (in the code above) re-defines the tickets variable to be... well, whatever it was before! Since "tickets" is defined by the user's input, it will be a string (user input is always a string.)

When the script gets to the next line (if tickets > tickets_remaining), it throws this error:

TypeError: '>' not supported between instances of 'str' and 'int'

That's because tickets_remaining is an integer, but tickets is a string.

You could make your code more efficient like this:

user_selection = int(input("How many tickets would you like to buy?")
    except ValueError:
        raise ValueError("Please enter only a number.")

Remember:

A Value error is raised when a built-in operation or function receives an argument that has the right type but an inappropriate value.

When we convert the user_selection input to an integer, Python will check to see if it's the right type. It will check for a string, since user input is always a string. Then it checks for an appropriate value- a string that can be converted into an integer (like "8").

Python will consider any non-number string as an inappropriate value. Thus, it will throw a ValueError. You can simplify the error handling that way.

Does this answer your question?

Yes, thank you so much!!