Question regarding local and global variables

[buran]

if in the local scope you try to assign to a name that is not being declared global, then it will be local (that is what happening in the first snippet)
In the second snippet you assign to a and b, so they again are local names. For c, you don't assign to c, you assign new value to element with index 0. That's the difference, you don't create new name c within the local scope, so it uses the one from the global scope. see the difference

a = 20
b = 30
c = [1, 2, 3]
print(f'outside, id: {id(c)}, c:{c}')
def demo():
    a = 21
    b = 31
    c = [4, 5, 6]
    print(f'inside, id: {id(c)}, c:{c}')
    c[0] = 7
    print(f'inside, id: {id(c)}, c:{c}')
     
demo()
print(f'outside, id: {id(c)}, c:{c}')

Output:
outside, id: 139836028387528, c:[1, 2, 3]
inside, id: 139836028387592, c:[4, 5, 6]
inside, id: 139836028387592, c:[7, 5, 6]
outside, id: 139836028387528, c:[1, 2, 3]