function - A simple math in Python that's hard for me

Question

Please help me. I'm trying to learn Python and I'm very beginner. I tried reading and watching videos but I don't understand this logic:

def myFunction(y):
    x = y + y #Local
    print(x)
    return x
x = 5 #Global
myFunction(x)
print(x)

I get the values 10 and 5.

Really, I can't understand why 10. This is breaking my mind. If x equals 5, than the result of the line 2 shouldn't be 2.5? I have 5 = y + y.

My mind is on a loop. Please help, you're my only hope.

Answer 1

You are passing x as the argument of your function myFunction(). Thus if x=5 you get:

myFunction(5):
   x = 5 + 5 
   return(x) #10

this is why you are getting 10. If you change x=5 to x=10 you will see that the result of the function will be 20 and so on...

You are not replacing the x in the function itself. However, the x you stated will indeed remain a global variable and thus will be printed on the second line.