Getter and Setter Methods

Getter and Setter methods provide a controlled way to read (get) and update (set) an object's attribute values, rather than allowing them to be accessed or modified directly - especially useful for private attributes.

Basic Getters and Setters

class Account:
    def __init__(self, balance):
        self.__balance = balance   # private attribute

    def get_balance(self):
        return self.__balance

    def set_balance(self, amount):
        if amount < 0:
            print("Balance cannot be negative")
        else:
            self.__balance = amount

acc = Account(1000)
print(acc.get_balance())   # 1000
acc.set_balance(2000)
acc.set_balance(-500)      # Balance cannot be negative

The setter method here adds validation logic, preventing the balance from ever being set to an invalid value - something direct attribute access wouldn't allow you to control.

A Cleaner Approach: the @property Decorator

Python's @property decorator lets you define getter and setter logic while still allowing the attribute to be accessed using simple, direct syntax rather than explicit method calls.

class Account:
    def __init__(self, balance):
        self.__balance = balance

    @property
    def balance(self):
        return self.__balance

    @balance.setter
    def balance(self, amount):
        if amount < 0:
            print("Balance cannot be negative")
        else:
            self.__balance = amount

acc = Account(1000)
print(acc.balance)   # 1000, reads like a plain attribute
acc.balance = 2000    # runs the setter logic behind the scenes

Coming Up Next

To close out this module, the final topic brings everything together with a complete Inheritance Case Study.