Functions and Classes

First PublishedFeb 10, 2026ByAtif Alam

Functions

def greet(name):
    return f"Hello, {name}"

def add(a, b):
    return a + b

Optional default arguments:

def say(msg, prefix=">"):
    return f"{prefix} {msg}"

Classes

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def greet(self):
        return f"Hi, I'm {self.name}"

p = Person("Alice", 30)
p.greet()   # "Hi, I'm Alice"

• __init__ is the constructor; self is the instance.
• Methods take self as the first parameter. You can nest data (attributes) and behavior (methods) in a class.