{"id":63,"date":"2026-03-01T15:51:43","date_gmt":"2026-03-01T10:51:43","guid":{"rendered":"https:\/\/gigz.pk\/python\/?post_type=lesson&p=63"},"modified":"2026-03-13T10:10:03","modified_gmt":"2026-03-13T05:10:03","slug":"defining-functions","status":"publish","type":"lesson","link":"https:\/\/gigz.pk\/python\/lesson\/defining-functions\/","title":{"rendered":"\u00a0Defining Functions"},"content":{"rendered":"\n

A function<\/strong> is a block of organized, reusable code that performs a specific task.
Functions help make programs shorter, cleaner, and easier to manage.<\/p>\n\n\n\n

Instead of writing the same code again and again, you can define it once and reuse it.<\/p>\n\n\n\n

WHY USE FUNCTIONS?<\/strong><\/h1>\n\n\n\n

\u2022 Reduce code repetition
\u2022 Improve readability
\u2022 Make programs modular
\u2022 Simplify debugging and maintenance<\/p>\n\n\n\n

SYNTAX OF A FUNCTION<\/strong><\/h1>\n\n\n\n
def function_name(parameters):
    # code block<\/pre>\n\n\n\n
\u2022 def<\/code> is the keyword used to define a function
\u2022 function_name<\/code> is the name of the function
\u2022 parameters<\/code> are optional inputs
\u2022 Indentation is required<\/p>\n\n\n\n
EXAMPLE 1: SIMPLE FUNCTION<\/strong><\/h1>\n\n\n\n
def greet():
    print(\"Hello, welcome to Python!\")greet()<\/pre>\n\n\n\n
When you call greet()<\/code>, the message is printed.<\/p>\n\n\n\n
FUNCTION WITH PARAMETERS<\/strong><\/h1>\n\n\n\n
You can pass values into a function.<\/p>\n\n\n\n
def greet(name):
    print(\"Hello\", name)greet(\"Hira\")<\/pre>\n\n\n\n
The function prints a personalized message.<\/p>\n\n\n\n
FUNCTION WITH RETURN VALUE<\/strong><\/h1>\n\n\n\n
Functions can return a result using the return<\/code> keyword.<\/p>\n\n\n\n
def add(a, b):
    return a + bresult = add(5, 3)
print(result)<\/pre>\n\n\n\n
The function calculates the sum and returns it.<\/p>\n\n\n\n
DEFAULT PARAMETERS<\/strong><\/h1>\n\n\n\n
You can provide default values to parameters.<\/p>\n\n\n\n
def greet(name=\"Guest\"):
    print(\"Hello\", name)greet()
greet(\"Ali\")<\/pre>\n\n\n\n
If no value is passed, the default value is used.<\/p>\n\n\n\n
KEY POINTS<\/strong><\/h1>\n\n\n\n
\u2022 Function names should be meaningful
\u2022 Always use parentheses when calling a function
\u2022 Use return when you need output from a function
\u2022 Indentation is very important<\/p>\n\n\n\n
WHY FUNCTIONS ARE IMPORTANT<\/strong><\/h1>\n\n\n\n
Functions are essential for building large applications.
They help organize code into manageable sections and make programs more efficient and professional.<\/p>\n\n\n\n
Understanding how to define and use functions is a fundamental skill in Python programming.<\/p>\n\n\n\n
<\/strong> 
<\/p> <\/div> <\/div>\n\n\n
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