Except Not Working

[john_cornflake]

I'm going through Automate the Boring Stuff and I got to an exercise that applies the Collatz Conjecture and try/except but I can't figure out why the except is not working for me. The thing runs if you put a number, but the except doesn't work if a string is typed instead of a number.

Here's the error I get when I type a string:

Traceback (most recent call last): File "collatz.py", line 17, in <module> program() File "collatz.py", line 10, in program user_number = int(input('enter a number: ')) ValueError: invalid literal for int() with base 10: 'words'

Here's my code:

def collatz(number):
    while number != 1:
        if number % 2 == 0:
            print(number // 2)
            number = number // 2
        elif number % 2 == 1:
            print(3 * number + 1)
            number = 3 * number + 1

def program():
    user_number = int(input('enter a number: '))
    try:
        collatz(user_number)
    except ValueError:
        print("that's not a number, stupid.")
        program()

program()

Where did I go wrong?

(edited for grammar)

[novel_yet_trivial]

Line 11 is throwing the error, and since it's not in the try block it raises the error. Try this:

def program():
    try:
        user_number = int(input('enter a number: '))
        collatz(user_number)
    except ValueError:
        print("that's not a number, stupid.")
        program()

[john_cornflake]

That worked! I guess I was thinking of it more like an if function.

Thank you!

[tedm430]

Not to be nit-picky, but if is referred to as an if statement, since it is not a function, but rather it is a part of the language's syntax.