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How to define a function in Python?

In Python, you can define a function using the def keyword followed by the function name and a pair of parentheses. 

Here's the general syntax for defining a function:

def function_name(parameters):
    # Function body
    # Code statements
    # Return statement (optional)

Let's break down the components of a function definition:

  • def: The def keyword is used to indicate the start of a function definition.
  • function_name: This is the name of the function. Choose a descriptive name that reflects the purpose or action performed by the function.
  • parameters: Inside the parentheses, you can specify any parameters or arguments that the function accepts. Parameters are placeholders for values that will be passed to the function when it is called. Multiple parameters are separated by commas.
  • Function body: The function body consists of one or more statements that define what the function does. Indentation is used to delimit the block of code that belongs to the function.
  • Return statement: The return statement is optional and is used to specify the value that the function should return. If no return statement is present, the function will return None by default.

Here's an example that defines a simple function called greet() that takes a name parameter and prints a greeting message:

def greet(name):
    print("Hello, " + name + "!")

# Function call
greet("John")

Output:

Hello, John!

In addition to defining the function, you can also call the function by using its name followed by parentheses. When the function is called, the code inside the function's body is executed, and any provided arguments are passed to the function.

Functions in Python allow you to encapsulate reusable blocks of code, enhance code organization, and promote code reusability. You can define functions at any point in your code, but it's common practice to define them before they are called to ensure their availability.

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