Python Constructor

A constructor is a special method that is used to initialize the instance variables of a class. In the constructor, we create the instance variables and initialize them with some starting values. The first parameter of the constructor will be 'self' variable that contains the memory address of the instance. For example,

Here, the constructor has only one parameter, i.e. 'self'. Using '' and 'self.marks', we can access the instance variables of the class. A constructor is called at the time of creating an instance. So, the above constructor will be called when we create an instance as:

s1 = Student()

Observe the empty parentheses after the class name 'Student'. These empty parentheses represent that we are not passing any values to the constructor. Suppose, we want to pass some values to the constructor, then we have to pass them in the parentheses after the class name.

Here, the formal arguments are 'n' and 'm' whose default values are given as ' ' (None) and 0 (zero). Hence, if we do not pass any values to constructor at the time of creating an instance, the default values of these formal arguments are stored into name and marks variables.

s1 = Student('Lakshmi Bai', 880)

In this case, we are passing two actual arguments: 'Lakshmi Bai' and 880 to the Student instance. Hence these values are sent to the arguments 'n' and 'm' and from there stored into name and marks variables.

A Python program to create Student class with a constructor having more than one parameter.