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Python Constructors
In this tutorial, we are going to learn Contructors in Python
In Python, a constructor is a special method that is automatically called when an object of a class is created. Constructors are used to initialize the attributes (properties) of an object. In Python, the constructor method is named __init__()
.
Here’s an example of a simple constructor in Python:
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
person1 = Person("Alice", 25)
print(person1.name) # Output: Alice
print(person1.age) # Output: 25
In the example above, we define a class called Person
. The __init__()
method takes three parameters: self
, name
, and age
. The self
parameter refers to the instance of the class, and it is automatically passed when an object is created. The name
and age
parameters are used to initialize the name
and age
attributes of the object.
When we create an instance of the Person
class using the Person("Alice", 25)
syntax, the __init__()
method is automatically called with the provided arguments. The name
and age
attributes of the object are then initialized with the corresponding values.
You can also define default values for the constructor parameters, making them optional:
class Person:
def __init__(self, name=None, age=None):
self.name = name
self.age = age
person1 = Person("Alice")
person2 = Person(age=25)
person3 = Person()
print(person1.name, person1.age) # Output: Alice None
print(person2.name, person2.age) # Output: None 25
print(person3.name, person3.age) # Output: None None
In this example, we can create instances of the Person
class with different combinations of provided arguments or no arguments at all. The attributes name
and age
will be initialized accordingly, with None
as the default value if no argument is provided.
Remember that the self
parameter is always required in the constructor method to refer to the instance being created.