Object methods and the init method

Object methods and the init method

In Python, the __init__() method is a special method that gets called when an object is created from a class. It is used to initialize the attributes of the object.

Here’s an example of a class with an __init__() method:

pythonCopy codeclass Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    
    def say_hello(self):
        print(f"Hello, my name is {self.name} and I'm {self.age} years old.")

In this example, the __init__() method takes two arguments, name and age, and initializes the name and age attributes of the object.

To create a new object from this class, we call the class like a function, passing any required arguments:

pythonCopy codep = Person("Alice", 25)

This creates a new Person object with the name attribute set to “Alice” and the age attribute set to 25.

We can then call the object’s methods, like say_hello(), which can access and operate on the object’s attributes:

pythonCopy codep.say_hello()  # prints "Hello, my name is Alice and I'm 25 years old."

In addition to the __init__() method, we can define other methods on a class that operate on the object’s attributes. These methods take the self parameter, which refers to the object that the method is being called on.

For example, here’s a class with a have_birthday() method that increments the age attribute of the object:

pythonCopy codeclass Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    
    def say_hello(self):
        print(f"Hello, my name is {self.name} and I'm {self.age} years old.")
    
    def have_birthday(self):
        self.age += 1

We can call the have_birthday() method on a Person object to increment its age attribute:

pythonCopy codep = Person("Alice", 25)
p.have_birthday()
p.say_hello()  # prints "Hello, my name is Alice and I'm 26 years old."

Overall, the __init__() method and other methods defined on a class allow us to create and manipulate objects in Python. They are a key part of object-oriented programming in Python.