Objects & Algorithms

Let's say we have a class such as:

class student:
	def __init__(self):
    	self.firstname = 'David'
        self.lastname = 'Joyner'
        
DJ = student()

in this code, we can say DJ is an instance, student is object

object is a general class that cannot be specified, and DJ is an instance that can be specified.

for the other example, we can say 'person' is object, 'David Joyner' is instance that exists only one in a world.

• Encapsulating Methods in Classes

Getter vs Setter difference

The biggest difference between Getters and Setters is that Getters return the value of the variable, and Setter changes the value of the variable.

Getters and setters has features following by:

• Let us log whenever a variable's value is accessed or changed
• let us prevent unauthorized access to instance variable's values
• let us build customized ways for modifying or retrieving instance variable's values

 

Now let's study about constructors in Python

class Person;
	def __init__(self, firstname="[no first name]",
    			lastname="[no last name]"):
        self.firstname = firstname
        self.lastname = lastname
        self.eyecolor = "[no eye color]"
        self.age = -1
        
myPerson = Person()
print(myPerson1.firstname)
myPerson2 = Person(firstname = "David")
myPerson3 = Person("Vrushali")
print(myPerson3.firstname)

in this code, the print outputs will be:

[no first name]
David
Vrushali

we can see if we don't put the arguments when we create new instance, it defaults to those default arguments

and when we put the argument such as firstname = "David" or "Vrushali", it overrides the default value