x = 5?

Question

x = 5
def (foo)
x=x
print(x)
foo()
Output: Error
#I remember that we cannot produce undefined things, but as x = 5 and x=x (so 5) shouldn't the output be 5? Thanks for any help:)

Answer 1

They are in different scopes. One is in the function scope while the other is in the global scope. To make the output 5 one can add this line to the function:
global x

Answer 2

You can use a global variable in your function, but you cannot change it.
x = 5 # global variable
def f():
print(x) # ok
def g():
x += 1 # error, need to use "global x"

Answer 3

Thanks everyone!