Python Methods: Bundling Data and Behavior in Objects | Khan Academy

Understanding Methods in Python

• 💡 A method is essentially a function that belongs to an object, defined on a specific data type.
• 🎯 Methods are used to access or update an object's attributes, bundling data and behavior together.

The Power of Encapsulation

• 🔑 Methods allow objects to manage their own data, a concept known as encapsulation.
• 🛡️ Outside code interacts with an object solely through its methods, protecting attributes from invalid changes.
• 🧩 This ensures that common logic, like rounding balances or validating transactions, is consistently applied.

Defining and Calling Methods

• ✍️ Methods are defined within a class definition, indented inside the class, which attaches the function to the data type.
• 📞 When calling a method on an object, Python automatically passes the object as the first argument (conventionally named self).
• ✨ Programmers typically use dot syntax (e.g., object.method()) for a more convenient way to call methods.

Mutator Methods and Validation

• 🔄 Methods can not only access data but also mutate (change) it, such as deposit or withdraw methods.
• ⚠️ It's crucial to implement validation logic within methods (e.g., preventing negative deposits or withdrawals exceeding the balance) to maintain data integrity.
• ✅ By defining all rules within the class (attributes and methods), we ensure safe and controlled interaction with objects.