2.3 Scope | Code Scholars Tutoring

How it works

Names assigned inside a function are local unless declared otherwise. Reading an outer name works; assigning to it creates a new local one.

Pass values in and return them out rather than reaching for globals.

Assigning to a name that also exists outside, which creates a local and leaves the outer one untouched.

Python

count = 10
def local_count():
    count = 3
    return count

print(local_count())
print(count)

Output

3
10

The assignment inside the function creates a local binding. It does not reassign the module-level name in this example.

Determine the exact output and explain the state changes.

Python

x = 5
def f(x):
    x += 1
    return x
print(f(x), x)

Show solution

Output

6 5

The parameter x is local, and incrementing that local integer binding does not change the caller binding.

Why is returning a value often clearer than changing a global variable?

Show solution

It makes the dependency and result explicit at the call site, reducing hidden shared state and simplifying isolated tests.