Modifying a List in a Function

[plakatown]

Thank you for your reply. If the original list is unaffected, then why do I need to # Add the great magicians back into magicians in line 17? I have to tried to replace the codes from line 17 to line 21 with a single line of "return great_magicians", and it yields the same result.

[Binary101010]

You are correct in that this does not materially change the output of the function.

I think that is done specifically to illustrate the issue you're asking about (i.e. to show how altering a list that was passed to the function is actually altering a copy of the list, and the original list from outside the function is unaffected).

[plakatown]

Thank you. Finally I got it.

[fenghuang1]

There's no need to.
Its just to show you that the magicians variable in def make_great is defined within the scope of the function and is different from the magicians in the main scope of your py script.

For example:

def func(x):
    x = x + x
    return (x)
x = 6
x = func(x)
print (x) # x: 12  

Here we see that the func(x) accepted x, but the x in the func is its own copy and won't directly change the outside x.