Now, having objects with attributes is great, but object-oriented programming is really about the interaction between objects. We're interested in invoking actions that cause things to happen to those attributes. We have data; now it's time to add behaviors to our classes.
Let's model a couple of actions on our Point class. We can start with a method called reset, which moves the point to the origin (the origin is the place where x and y are both zero). This is a good introductory action because it doesn't require any parameters:
class Point:
def reset(self):
self.x = 0
self.y = 0
p = Point()
p.reset()
print(p.x, p.y)
This print statement shows us the two zeros on the attributes:
0 0
In Python, a method is formatted identically to a function. It starts with the def keyword , followed by a space, and the name of the method. This is followed by a set of parentheses containing the parameter list (we'll discuss that self parameter in just a moment), and terminated with a colon. The next line is indented to contain the statements inside the method. These statements can be arbitrary Python code operating on the object itself and any parameters passed in, as the method sees fit.