Why use Classes?

What is a Python Class?

A Python class is like a template or blueprint for creating objects — in this example, our class creates tools to check if the condensation is likely to occur based on temperature and dew point at a certain location.

Think of it like this:
- A function does one task.
- A class bundles together data and functions (called methods) that relate to a single concept — like checking condensation.

For example:

class CondensationChecker:
    def __init__(self, location, temperature_c, dew_point_c):
        self.location = location
        self.temperature_c = temperature_c
        self.dew_point_c = dew_point_c

    def check_condensation(self):
        return self.temperature_c <= self.dew_point_c

    def report(self):
        # Prints the current condition and whether condensation is likely

Here:
The data: temperature, dew point, location
The behavior: check_condensation(), report()

What are Classes used for?

In this example, we use a class to create objects that represent weather conditions that will be used to check if condensation is likely to occur.

station = CondensationChecker("Berlin", 12.0, 12.5)
station.report()

The object station holds its own data and can run its own analysis on the data provided.

Why use a Class instead of just functions?

Let's compare using a class vs. just using functions.

With just functions:

def check_condensation(temp, dew_point):
    return temp <= dew_point

You’d need to manually pass temperature and dew point every single time, and it doesn't naturally group this data together. You also can't easily add more features like location, time, or logging.

With a class:

station = CondensationChecker("Berlin", 12.0, 12.5)
station.report()

This is a much cleaner option — all related data is stored inside the object, and methods operate on that data.

Benefits of using a Class

Organization: Grouping Related Data and Behavior

A class brings data and the functions that operate on it together in one place.

In CondensationChecker:
The data: temperature, dew point, location
The behavior: check_condensation(), report()

These things belong together logically. Instead of keeping temperature and dew point as separate variables and writing separate functions, the class keeps them bundled as one logical unit.

Reusability: Create Many Independent Instances

You can reuse the same class to create multiple objects representing different conditions — without repeating code.

Example:

station1 = CondensationChecker("London", 15, 12)
station2 = CondensationChecker("Barcelona", 28, 27)

station1.report()
station2.report()

Each station is independent, and the logic to check condensation is shared and reusable.

Without a class, you'd have to manage multiple sets of variables manually and pass them into functions every time — more error-prone and harder to manage.

Extensibility: Easy to Add New Features

When your code grows in complexity, classes make it easy to add new functionality without breaking existing logic.

For example, you can add a method to estimate relative humidity based on existing data:

def estimate_relative_humidity(self):
    # Use formula here

This method now becomes part of the condensation checker — you don’t have to touch outside code.

Modularity

Classes act like building blocks for larger systems. You can isolate pieces of your program into logical units.

Maintainability and Cleanliness: Easier to Read, Debug, and Scale

When your project grows, keeping code maintainable is very important.

With a class:
- Each part of the program has a clear purpose.
- You can fix or update just one class without affecting others.
- You don’t have to trace global variables across multiple files.

If someone new joins your team, they can understand what CondensationChecker does just by reading that one class.