When to Use Functions and Classes

Welcome to this guide on deciding when to use functions or classes in Python. Understanding this can significantly enhance your coding skills and project organization. Let’s explain this using examples.

Let’s talk about functions first

Functions are your go-to for tasks that can be separated from the object’s state. They are perfect for carrying out specific calculations or operations that do not require saving any information or state between executions.

Example 1: Calculate the Area of a Circle

This function calculates the area of a circle given its radius. This is a typical use case for a function because it performs a calculation without needing to remember any previous state.

def calculate_area(radius):
    pi = 3.14159
    return pi * (radius ** 2)

# Usage
print(calculate_area(5))  # Outputs 78.53975

Example 2: Check Prime Number

This function checks whether a number is prime. It’s a good example of a function because it evaluates each number independently of other numbers.

def is_prime(num):
    if num <= 1:
        return False
    for i in range(2, int(num**0.5) + 1):
        if num % i == 0:
            return False
    return True

# Usage
print(is_prime(29))  # Outputs True
print(is_prime(15))  # Outputs False

Let’s now have a look at classes

Classes are suited for more complex tasks that involve managing multiple related properties and behaviors/methods. They allow you to encapsulate data and functions together, making the code more modular and easier to understand.

Example 1: Bank Account Manager

This class manages a bank account, allowing for deposits and withdrawals, which involves maintaining the state of the account balance.