Variable Assignment in Functions

def foo(x): x = 5 return x y = 10 result = foo(y) print(y) ```

Understanding variable scope and assignment in Python functions

This is a fundamental Python question that tests whether you understand how assignment and scope work inside function definitions. It's the kind of question that separates candidates who can reason about code behavior from those who make assumptions.

The core concept is distinguishing between reassigning a local variable inside a function versus modifying state that persists outside it. When you pass an argument to a function and then assign to that parameter, you're creating a new binding in the function's local scope—you're not changing the original variable in the caller's scope. This is crucial for writing correct code and debugging unexpected behavior.

• Local vs. global scope and the scope resolution order
• Parameter passing and variable binding in Python
• The difference between reassignment and mutation