why did he have to call err

The whole idea behind try, except and else is that they are meant to handle AUTOMATIC ERRORS OF Python. While Raise SomeError is meant to handle MANUAL ERRORS OF CHOICE and then run these manual errors in the except block.

Thanks Mark - so if I'm understanding this correctly, then:

1. The automatic error happens because Python itself recognizes that an answer isn't able to be computed (i.e. answers as a string rather than a number that can then be coerced)

2. The raised error is when a user could enter something that can be coerced (such as a negative number), but logically it doesn't make sense (as in there can't be negative numbers of people), and we raise an error to prevent such a thing from happening.

Yes?

Great question,

def split_check(total, number_of_people):
    if number_of_people <= 1:
        raise ValueError("More than 1 person is required to split the check")
    return math.ceil(total / number_of_people)


try:
    total_due = float(input("What is the total?"))
    number_of_people = int(input("How many people?"))
    amount_due = split_check(total_due, number_of_people)
except ValueError as err:
    print("That's not a valid value")
    print("({})".format(err))
else:
    print("each person owes {}".format(amount_due))

Let me break down what the program is doing in order:

1. Takes the output of the first input and stores it in the variable total_due.
2. Takes the output of the second input and stores it in the variable number_of_people.
3. Calls the function and stores the return value in the variable amount_due.

Let me stop here for a minute. When the function gets called, it checks the number of people. If it equals or less than 1 it raises a ValueError("message"). It's called a raise exception(args). Therefore when you use that method, the args will be printed when you print the exception object. Example:

try:
    raise ValueError("Raised an exception")
except ValueError as err:
    print(err)

So what's happening is when the function is called and an error is thrown the args gets used (which is the message). Try inputting a letter instead of a number, it's not gonna throw the same error message because the function hasn't been called.

I hope this helps :)

I think I might have the same question as you (if I'm understanding yours correctly).

I'm wondering why we have two print statements that could be combined. Is it that the line

except ValueError as err:

prints something that could work for any part of the try (e.g. if the user inputs something other than an item that can be converted as a float, for example if they put in characters or letters)...

...and then the lines

if number_of_people <= 1:
        raise ValueError("More than 1 person is required to split the check")

are specifically for the number_of_people.

It seems a bit more complicated than necessary.

So if the user gives an invalid answer to total_due, then it's going to give one error message. If the user gives an invalid answer to number_of_people, then it gives two error messages. Is there a reason for this?

Katie Ferencik you're welcome! <3

I have the same question as Katie Ferencik above! Why would we want the error message created for when the user enters a string for when they enter a value that is <= 0?

Also, could someone explain to me how the following: except ValueError as err: print("Oh no! That's not a valid value. Try again...") print("({})".format(err))

Calls the value we set in: def split_check(total, number_of_people): if number_of_people <= 1: raise ValueError("More than 1 person is required to split the check") return math.ceil(total / number_of_people)

I've rewatched the video many times but I'm not getting it