Python-class and Objects

Object-oriented programming

Python is OOP, usually, each object definition corresponds to some object or concept in the real world a nd the functions that operate on that object correspond to the ways Real-world objects interact.

In Python, every value was actually an object. An object with a state and a collection of methods that it can perform.

The state of an object represents those things, the object knows about itself.

User Defined Classes

1  class Point : 3     """  "" "45     def__init__(self):6 "" "" ""         7self.x = 0 8                   SELF.Y = 0

Every class should has a method with the special name _init_. This is Initializer method often called constructor.

A method behaves like a function but it's invoked on a specific instance.

The _str_ method is responsible for returning a string representation as defined by the class creator.

classPoint :"""Point class for representing and manipulating X, y coordinates."""    def __init__(self, INITX, inity):"""Create A new point at the origin"""self.x=INITX self.y=Inity

def _str_ (self):
Return "x=" + str (self.x) + ", y=" + str (SELF.Y)
　　
def GetX (self):
Return self.x

def GetY (self):
Return SELF.Y

def distancefromorigin (self):
Return ((self.x * 2) + (SELF.Y * 2)) * * 0.5

def halfway (self, target):
MX = (self.x + target.x)/2
my = (self.y + target.y)/2
Return point (MX, my)

def distance (Point1, Point2):
Xdiff = Point2.getx ()-Point1.getx ()
Ydiff = Point2.gety ()-point1.gety ()

Dist = MATH.SQRT (Xdiff * * 2 + ydiff * * 2)
Return Dist
P= Point (7,6)#instantiate an object of type pointQ = Point (2,2)#And make a second pointMID = P.halfway (q)

Print (mid)
Print (Mid.getx ())
Print (Mid.gety ())Print(P)
Print (P.getx ())
Print (P.gety ())
Print (P.distancefromorigin ())Print(q) Print (distance (p,q))Print(p isQ

Python-class and Objects