How would I access variables from one class to another

Question

I am writing a program that is utilizing multiple classes   I have one class that is dedicated to determining values for a set of variables   I would then like to be able to access the values of those variables with other classes   My code looks as follows   class ClassA object       def   init   self           self var1   1         self var2   2      def methodA self           self var1   self var1   self var2         return self var1   class ClassB ClassA       def   init   self           self var1             self var2      object1   ClassA   sum   object1 methodA   print sum   I use classA to initialize 2 variables  var1 and var2    I then use methodA to add them  saving the result as var1  I think this will make var1   3 and var2   2    What I want to know is how would I have ClassB then be able to get the values for var1 and var2 from ClassA

User · Answer

Can you explain why you want to do this   You re playing around with instance variables attributes which won t migrate from one class to another  they re bound not even to ClassA  but to a particular instance of ClassA that you created when you wrote ClassA      If you want to have changes in one class show up in another  you can use class variables   class ClassA object      var1   1    var2   2     classmethod    def method cls          cls var1   cls var1   cls var2        return cls var1   In this scenario  ClassB will pick up the values on ClassA from inheritance   You can then access the class variables via ClassA var1  ClassB var1 or even from an instance ClassA   var1  provided that you haven t added an instance method var1 which will be resolved before the class variable in attribute lookup   I d have to know a little bit more about your particular use case before I know if this is a course of action that I would actually recommend though

User · Answer

class ClassA object       def   init   self           self var1   1         self var2   2     def method self           self var1   self var1   self var2         return self var1  class ClassB ClassA       def   init   self           ClassA   init   self   object1   ClassA    sum   object1 method     object2   ClassB    print sum

User · Answer

Just create the variables in a class  And then inherit from that class to access its variables  But before accessing them  the parent class has to be called to initiate the variables  class a      def func1 self           a var1    quot Stack  quot   class b      def func2 self           b var2    quot Overflow quot   class c a b       def func3 self           c var3   a var1   b var2         print c var3   a   func1   b   func2   c   func3

User · Answer

var1 and var2 are instance variables  That means that you have to send the instance of ClassA to ClassB in order for ClassB to access it  i e   class ClassA object       def   init   self           self var1   1         self var2   2      def methodA self           self var1   self var1   self var2         return self var1    class ClassB ClassA       def   init   self  class a           self var1   class a var1         self var2   class a var2  object1   ClassA   sum   object1 methodA   object2   ClassB object1  print sum   On the other hand - if you were to use class variables  you could access var1 and var2 without sending object1 as a parameter to ClassB    class ClassA object       var1   0     var2   0     def   init   self           ClassA var1   1         ClassA var2   2      def methodA self           ClassA var1   ClassA var1   ClassA var2         return ClassA var1    class ClassB ClassA       def   init   self           print ClassA var1         print ClassA var2  object1   ClassA   sum   object1 methodA   object2   ClassB   print sum   Note  however  that class variables are shared among all instances of its class

User · Answer

we can access pass arguments variables from one class to another class using object reference   Class1 class Test      def   init   self           self a   10         self b   20         self add   0      def calc self           self add   self a self b   Class 2 class Test2      def display self           print  adding of two numbers    self add   creating object for Class1 obj   Test    invoking calc method   obj calc    passing class1 object to class2 Test2 display obj

User · Answer

var1 and var2 is an Instance variables of ClassA  Create an Instance of ClassB and when calling the methodA it will check the methodA in Child class  ClassB  first  If methodA is not present in ClassB you need to invoke the ClassA by using the super   method which will get you all the methods implemented in ClassA  Now  you can access all the methods and attributes of ClassB  class ClassA object       def   init   self           self var1   1         self var2   2      def methodA self           self var1   self var1   self var2         return self var1   class ClassB ClassA       def   init   self           super     init             print  quot var1 quot  self var1          print  quot var2 quot  self var2    object1   ClassB   sum   object1 methodA   print sum

[python] How would I access variables from one class to another?

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