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pythonclassclass-variables

How to access a class variable from another class in python?


I have the following code segment :

class A:
    def __init__(self):
        self.state = 'CHAT'

    def method1(self):
        self.state = 'SEND'

    def printer(self):
        print self.state


class B(A):
    def method2(self):
        self.method1()
        print self.state

ob_B = B()
ob_A = A()
ob_B.method2()
ob_A.printer()

This gives me the output :

SEND
CHAT

I want it to print :

SEND
SEND

That is, when B.method2 is modifying self.state by calling self.method1, I want it to modify the already existing value of self.state = 'CHAT' in A's instance. How can I do this?


Solution

  • The instance is passed as the first argument to each of your methods, so self is the instance. You are setting instance attributes and not class variables.

    class A:
    
        def __init__(self):
            A.state = 'CHAT'
    
        def method1(self):
            A.state = 'SEND'
    
        def printer(self):
            print A.state
    
    
    class B(A):
        def method2(self):
            self.method1()
            print B.state
    
    ob_B = B()
    ob_A = A()
    ob_B.method2()
    ob_A.printer()
    

    SEND
    SEND