Functions

Python Programming For Beginners

About Lesson

Defining and Calling Functions

Definition: A function is a block of reusable code that performs a specific task. Functions help in organizing code and avoiding repetition.

Syntax: python

def function_name(parameters): # code block return value

Example: python
```
def greet(name): return f"Hello, {name}!" print(greet("Alice"))
```
- Explanation: The def keyword is used to define a function. greet is the function name, and name is the parameter. The function returns a greeting message.

Function Arguments and Return Values

Arguments: Values passed to a function when it is called. They can be positional or keyword arguments.
- Positional Arguments: Passed in the order they are defined.
- Keyword Arguments: Passed with the parameter name, allowing out-of-order passing.
python
```
def add(a, b): return a + b print(add(2, 3)) # Positional print(add(b=3, a=2)) # Keyword
```
Return Values: The value that a function returns using the return statement. If no return statement is used, the function returns None. python
```
def square(x): return x * x result = square(4) print(result) # Output: 16
```