David J Nevin+= Code

Last updated: Jun 27, 2022

Classes and Objects

Classes and Methods: Some Notes

If you don’t initialize the values of properties, the code will not compile. Initializing the values of properties inside the class is necessary.

Class variables

The class variables are shared by all instances or objects of the classes. A change in the class variable will change the value of that property in all the objects of the class.

Instance variables

The instance variables are unique to each instance or object of the class. A change in the instance variable will change the value of the property in that specific object only.

Method Overloading

A method can be made to preform different operations by overloading it. In Python, as opposed to C# for example, methods must be implicitly overloaded.

Types of Methods

Instance methods, class methods, and static methods.

Class Methods

Class methods are accessed using the class name and not the object, and they don;t require an object to be created to be accessed.

We use the @classmethod decorator, and we use cls to refer to the class as we used self to refer to the object.

Static Methods

Static methods are usually limited to the class only and not their objects. They can be used as utilities for the class.

We use the @staticmethod decorator and we don’t use a reference to the method, such as self or cls.

Static methods have no knowledge of class variables or state, and so cannot modify class attributes.

Access Modifiers

By default all methods and properties in a class are publicly available. Properties can be set to “private” by using the __ before the property name. Attempting to access this property will cause an error.


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