Question

Make yet another class called, of course, Thing3. This time, assign the value ' \(x y z\) ' to an instance (object) attribute called letters. Print letters. Do you need to make an object from the class to do this?

Short answer

Yes, you need to create an object from the `Thing3` class to access and print the `letters` attribute.

Step-by-step solution

Create the Class

Define a new class named `Thing3`. This is done by using the keyword `class` followed by the class name.

Add an Instance Attribute in the Constructor

Inside the class `Thing3`, define a constructor method `__init__(self)`. Use this method to initialize the instance attribute `letters` with the value `'xyz'`.

Create an Object from the Class

In order to access the instance attribute, create an object by calling the class `Thing3()`, which invokes the constructor to initialize `letters`.

Print the Attribute

Use the object created in Step 3 to access and print the `letters` attribute using the syntax `object_name.letters`.

Key concepts

Understanding Class Definitions

In Python, a class is like a blueprint for creating objects. It defines a new type that allows you to create instances with specific attributes and methods. A class definition begins with the keyword `class` followed by the class name. For example, in the exercise, we define a class named `Thing3` as follows:
```python class Thing3: pass ``` This simple setup establishes `Thing3` as a new class but doesn't add any functionality yet. It serves as a template from which we can build objects. By defining a class, you are essentially laying down the framework for future specific data (attributes) and functionalities (methods) to be encapsulated within this class structure.

Exploring Instance Attributes

Instance attributes in a class are variables that hold data specific to each object created from the class. An instance attribute is defined within the `__init__()` method, which is also known as the constructor. In this method, you can initialize variables to hold specific values for each instance:
```python class Thing3: def __init__(self): self.letters = 'xyz' ``` Here, `letters` is an instance attribute initialized with the string value `'xyz'`. This means every object created from `Thing3` will have its own copy of `letters`. Accessing these attributes is straightforward. You use the syntax `object_name.attribute_name`. This design allows each object to carry and manage its own data efficiently, making object-oriented programming a powerful paradigm.

Object Instantiation Demystified

Object instantiation is the process of creating a specific object from a class. This is done by calling the class as if it were a function. During this process, the `__init__()` constructor is automatically invoked, initializing the object's attributes. From our exercise example:
```python thing = Thing3() ``` Here, `thing` becomes an instance of the `Thing3` class. The constructor method inside the class is called, setting up the value of `letters` for this particular object. Once instantiated, you can access and manipulate the object's instance attributes like `letters`. To check the attribute's value, use `thing.letters`, which will return `'xyz'`. This combination of defining classes, adding attributes, and instanting objects is fundamental in building complex and reusable code structures.