I have a question to RAISE

I am too really confused on this matter, i mean there are too much examples and not much explanations, i belive people want to hear a real explanation on like what it is and where you can use it, not like in this particular example

Imagine other code using the split_check function. By including the exception pattern, anyone who uses that function, not just our main code, will benefit.

This is logic that can be expressed within the function, and in all cases is what should happen, whenever that function is used. If we don't do it, everyone using the function will need to think about that exceptional behavior themselves.

This is really more about code reuse than anything else. Oftentimes you'll create your own Exception type and use it to explain to others as to how to use objects that you are defining.

I definitely am bending the example in our case to show how to raise an exception.

That clear things up?

Here is the official tutorial on errors and exceptions.

I've been struggling with this myself in recent days. So answering this question will hopefully help us both out. But there is a discernable difference.

Let's look at the script in question.

import math

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


try:
    total_due = float(input("What is the total?   "))
    num_people = int(input("How many people?   "))
    amount_due = split_check(total_due, num_people)

except ValueError as err:
    print("Sorry, this is not a valid value.")
    print("({})".format(err))

else:
    #run code if no exceptions
    print("Each person owes ${}".format(amount_due))

When you're using a try catch block, you're checking for code that might fail and checking it against a particular type of exception, and then coercing the interpreter to display the error in a more user friendly way.

So we use raise to catch what is specifically wrong... but with try we're catching the code that won't run because something has gone wrong.

In this case, someone has put a value in that doesn't work for the program.

hmm, could we not handle it with an, if else block?

while true:
    if num_people <= 1:
        print("More than 1 person is required to split the check")
        continue

Craig Dennis could you help shed some light on this?

Thanks