Python functions and variable scope exam review

What is a function in Python?

A function is a block of reusable code that performs a specific task. It is defined using the 'def' keyword.

What are parameters in a function?

Parameters are variables listed inside the parentheses in a function definition. They allow you to pass information into the function.

True or False: Functions can return multiple values.

True. Functions can return multiple values as a tuple, allowing the caller to receive several results at once.

Fill in the blank: Use the ______ keyword to define a function.

'def'

How do you call a function?

You call a function by using its name followed by parentheses, e.g., 'my_function()'.

What is the return value of a function?

The return value is the output that a function sends back to the caller using the 'return' statement.

Compare 'return' vs. 'print' in functions.

'return' sends a value back to the caller, while 'print' displays output to the console without returning anything.

Cause → Effect: What happens if you omit the return statement?

The function will return 'None' by default, meaning no value is sent back to the caller.

What is a default parameter?

A default parameter is a parameter that assumes a default value if no argument is passed during the function call.

How to define a function with default parameters?

Example: 'def greet(name='User'):' sets 'User' as the default value for 'name' if not specified.

What is the purpose of *args in a function?

'*args' allows a function to accept any number of positional arguments, packing them into a tuple.

Explain the use of **kwargs.

'**kwargs' allows a function to accept any number of keyword arguments, packing them into a dictionary.

What is a local variable?

A local variable is defined within a function and only accessible within that function's scope.

True or False: Global variables can be accessed anywhere in the code.

True. Global variables are defined outside any function and can be used throughout the entire module.

Define a global variable.

A global variable is declared outside of all functions and is available to all functions within the same module.

What does the nonlocal keyword do?

The nonlocal keyword allows you to assign a value to a variable in the nearest enclosing scope that is not global.

Local vs Global: What's the difference?

- Local: Accessible only within the function. - Global: Accessible throughout the entire module.

Fill in the blank: A __________ variable exists only within a specific block of code.

Local

What happens if you use a global variable in a function without declaring it?

Python treats it as a local variable unless declared with the 'global' keyword, leading to an UnboundLocalError.

Cause: Assigning a value to a variable inside a function.

Effect: The variable is treated as local unless explicitly marked as global.

True or False: Nonlocal variables can be used in nested functions.

True. Nonlocal variables help to access variables from the nearest enclosing scope, excluding globals.

What is the scope of a variable defined inside a loop?

The variable has a local scope, accessible only within the loop unless declared otherwise.

Demonstrate local variable scope with an example.

def example(): x = 5 example() print(x) # Raises NameError: name 'x' is not defined.

Global variable example.

x = 10 def display(): print(x) display() # Outputs: 10