whats the difference

I assume that you want to know why you would care to use else in a try/except clause. Pardon me if I'm wrong.

Let's say that we get input (as a string) from a user, and we want to convert it into an integer. Of course, some mischievous user might enter some non-integer, such as "abc", and Python will throw an error. Not user-friendly at all!

Solution:

user_input = input('Enter a number: ')
try:
    num = int(user_input)
except ValueError:
    print('Please enter a number.')

Now, once the user types in a non-integer, we catch the error and respond with a more friendly message. But the user can't re-enter the number and have another chance! Let's use a loop.

while True:
    user_input = input('Enter a number: ')
    try:
        num = int(user_input)
        break
    except ValueError:
        print('Please enter a number.')

Now, this works, but most people reading this code would have to scratch their head a little bit to understand it. This is because break is in an awkward place: in the try block.

Of course, this is a matter of preference, but I (and many people) prefer to write:

while True:
    user_input = input('Enter a number: ')
    try:
        num = int(user_input)
    except ValueError:
        print('Please enter a number.')
    else:
        break

I hope this helps. ~Alex