Functions in Python

Functions let you organize code into reusable blocks.

Defining a Function

We define a function in Python with the use of def(). Below is an example.

def greet():
    print("Hello, welcome to Python!")
    
greet()

Parameters and Arguments

We pass parameters and arguments through functions like in the example below.

def add(a, b):
    return a + b
result = add(10, 5)
print(result)   # 15

Default Parameters

def greet_user(name="Guest"):
    print(f"Hello, {name}!")
greet_user()         # Hello, Guest!
greet_user("Zarine") # Hello, Zarine!

Keyword Arguments

def student_info(name, branch, year):
    print(f"{name} studies {branch} in year {year}")
student_info(branch="ECE", year=2, name="Zarine")

Variable Arguments (*args, **kwargs)

def add_all(*nums):
    return sum(nums)
print(add_all(1, 2, 3, 4))  # 10

Lambda Functions

square = lambda x: x * x
print(square(5))   # 25

📝 Quick Exercises

• Write a function multiply(x, y) that returns the product.
• Write a function is_even(num) that prints "Even" or "Odd".
• Create a lambda function that reverses a string.