Python 3 Object-Oriented Programming - Third Edition

Adding attributes

Now, we have a basic class, but it's fairly useless. It doesn't contain any data, and it doesn't do anything. What do we have to do to assign an attribute to a given object?

In fact, we don't have to do anything special in the class definition. We can set arbitrary attributes on an instantiated object using dot notation:

class Point: 
    pass 
 
p1 = Point() 
p2 = Point() 
 
p1.x = 5 
p1.y = 4 
 
p2.x = 3 
p2.y = 6 
 
print(p1.x, p1.y) 
print(p2.x, p2.y) 

If we run this code, the two print statements at the end tell us the new attribute values on the two objects:

5 4
3 6

This code creates an empty Point class with no data or behaviors. Then, it creates two instances of that class and assigns each of those instances x and y coordinates to identify ...