Function Definition and Call in Python

In Python, functions are defined using the def keyword, followed by the function name and parentheses. This section will explain how to define a function and how to call it to execute the code within it.

Key Points on Function Definition and Call:

• Function Definition: A function is defined using the def keyword, which indicates the start of a function block.
• Function Name: The name of the function should be descriptive, indicating its purpose, and must follow the naming conventions of Python.
• Parameters: Functions can take parameters, which allow you to pass data into them for processing.
• Function Body: The code block that performs the desired action is indented under the function definition.
• Return Statement: Functions can return a value using the return statement, allowing them to output results to the caller.
• Function Call: A function is called by using its name followed by parentheses, which can include arguments if the function accepts parameters.
• Executing Code: Only when a function is called does the code inside it execute, making functions reusable and modular.
• Optional Parameters: Parameters can have default values, making them optional during function calls.

Example of Function Definition and Call:

def add_numbers(a, b):
            return a + b
        
        # Function call
        result = add_numbers(5, 10)
        print(result)  # Output: 15

Detailed Explanation:

• Function Definition: The function add_numbers is defined with two parameters, a and b, which are used to perform the addition.
• Function Body: The body of the function contains a single statement that returns the sum of a and b.
• Function Call: The function is called with the arguments 5 and 10, and the result is stored in the variable result.
• Output: The print statement displays the result of the function call, which is 15.

Understanding how to define and call functions is fundamental in Python programming, enabling developers to create efficient, reusable, and organized code.