Module 19 Knowledge Check - Understanding Scope

1. What is a 'local variable' in Python?

A variable accessible from anywhere in the program. A variable defined inside a function and only usable within that function. A special type of variable used only for loops. A variable that stores text data.

2. What is a 'global variable' in Python?

A variable defined outside of any function, typically at the top level of a script. A variable that can only be used inside one specific function. A variable that automatically stores the result of the last calculation. Another name for a function parameter.

3. Consider the following code:

message = "Hello"

def greet():
    message = "Hi"
    print(message)

greet()
print(message)

What will be printed?

Hello
Hello Hi
Hi Hello
Hi Hi
Hello

4. Where can a variable defined *inside* a function (without using `global`) be accessed?

Only outside the function. Both inside and outside the function. Only inside that specific function. Only in other functions called by this function.

5. Why is understanding scope important in programming?

It helps avoid naming conflicts and makes code easier to understand and debug. It makes the program run faster. It's only important for very large and complex programs. It determines the data type of a variable.

6. If a function needs to modify a global variable, what keyword might it need to use *inside* the function before assigning a new value to that variable?

`local` `global` `var` `def`

7. Consider this code:

count = 0

def increment():
    count = count + 1 # Attempts to modify 'count'
    print(count)

increment()

What is the most likely outcome when running this code?

It prints 1. It prints 0. It prints nothing. It causes an `UnboundLocalError` because `count` is referenced before assignment within the local scope.

8. Can a function access a global variable without using the `global` keyword?

Yes, if it's only reading the value (not trying to change it). No, the `global` keyword is always required to access global variables inside functions. Only if the global variable is a number. Only if the function has no parameters.

9. What is the scope of a variable defined in a `for` loop statement (like `i` in `for i in range(5):`) within a function?

Global scope. A special "loop scope", only accessible inside the loop block. Local scope (belonging to the function the loop is in). It doesn't have a scope.

10. If you define a variable inside a function, and then the function finishes executing, what happens to that local variable?

It becomes a global variable automatically. It typically disappears and its memory is reclaimed (garbage collected). It remains accessible, but only if you call the function again. It gets stored in a special file.