How to call a Parent Class s method from Child Class in Python

Question

When creating a simple object hierarchy in Python  I d like to be able to invoke methods of the parent class from a derived class   In Perl and Java  there is a keyword for this  super    In Perl  I might do this   package Foo   sub frotz       return  Bamf      package Bar   ISA   qw Foo    sub frotz      my  str   SUPER  frotz       return uc  str       In Python  it appears that I have to name the parent class explicitly from the child  In the example above  I d have to do something like Foo  frotz       This doesn t seem right since this behavior makes it hard to make deep hierarchies   If children need to know what class defined an inherited method  then all sorts of information pain is created     Is this an actual limitation in python  a gap in my understanding or both

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class a object       def my hello self           print  hello ravi   class b a       def my hello self       super b self  my hello       print  hi   obj   b   obj my hello

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Python also has super as well    super type   object-or-type       Return a proxy object that delegates method calls to a parent or sibling class of type    This is useful for accessing inherited methods that have been overridden in a class     The search order is same as that used by getattr   except that the type itself is skipped    Example    class A object         deriving from  object  declares A as a  new-style-class      def foo self           print  foo   class B A       def foo self           super B  self  foo       calls  A foo     myB   B   myB foo

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Many answers have explained how to call a method from the parent which has been overridden in the child   However       how do you call a parent class s method from child class     could also just mean       how do you call inherited methods      You can call methods inherited from a parent class just as if they were methods of the child class  as long as they haven t been overwritten   e g  in python 3   class A      def bar self  string       print  Hi  I m bar  inherited from A  string   class B A     def baz self       self bar   - called by baz in B    B   baz     prints out  Hi  I m bar  inherited from A - called by baz in B    yes  this may be fairly obvious  but I feel that without pointing this out people may leave this thread with the impression you have to jump through ridiculous hoops just to access inherited methods in python  Especially as this question rates highly in searches for  how to access a parent class s method in Python   and the OP is written from the perspective of someone new to python   I found  https   docs python org 3 tutorial classes html inheritance to be useful in understanding how you access inherited methods

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There s a super   in Python too  It s a bit wonky  because of Python s old- and new-style classes  but is quite commonly used e g  in constructors   class Foo Bar       def   init   self           super Foo  self    init             self baz   5

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Use the super   function  class Foo Bar       def baz self  arg           return super   baz arg   For Python  lt  3  you must explicitly opt in to using new-style classes and use  class Foo Bar       def baz self  arg           return super Foo  self  baz arg

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If you don t know how many arguments you might get  and want to pass them all through to the child as well   class Foo bar      def baz self  arg   args    kwargs                 Do your thing         return super Foo  self  baz arg   args    kwargs     From  Python - Cleanest way to override   init   where an optional kwarg must be used after the super   call

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Python 3 has a different and simpler syntax for calling parent method   If Foo class inherits from Bar  then from Bar   init   can be invoked from Foo via super     init       class Foo Bar        def   init   self   args    kwargs             invoke Bar   init           super     init    args    kwargs

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I would recommend using CLASS   bases   something like this  class A     def   init   self           print  I am Class  s  self   class     name           for parentClass in self   class     bases                  print     I am inherited from   parentClass   name                  parentClass foo self   lt - call parents function with self as first param class B A  pass class C B  pass a b c   A   B   C

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ImmediateParentClass frotz self    will be just fine  whether the immediate parent class defined frotz itself or inherited it   super is only needed for proper support of multiple inheritance  and then it only works if every class uses it properly    In general  AnyClass whatever is going to look up whatever in AnyClass s ancestors if AnyClass doesn t define override it  and this holds true for  child class calling parent s method  as for any other occurrence

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In Python 2  I didn t have a lot luck with super     I used the answer from  jimifiki on this SO thread how to refer to a parent method in python   Then  I added my own little twist to it  which I think is an improvement in usability  Especially if you have long class names    Define the base class in one module      myA py  class A             def foo  self            print  foo    Then import the class into another modules as parent     myB py  from myA import A as parent  class B  parent        def foo  self            parent foo  self       calls  A foo

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class department      campus name  attock      def printer self           print self campus name   class CS dept department       def overr CS self           department printer self          print  i am child class1    c CS dept   c overr CS

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There is a super   in python also   Example for how a super class method is called from a sub class method  class Dog object       name          moves           def   init   self  name           self name   name      def moves setup self x           self moves append  walk           self moves append  run           self moves append x      def get moves self           return self moves  class Superdog Dog         Let s try to append new fly ability to our Superdog     def moves setup self            Set default moves by calling method of parent class         super   moves setup  hello world           self moves append  fly   dog   Superdog  Freddy   print  dog name  dog moves setup   print  dog get moves       This example is similar to the one explained above However there is one difference that super doesn t have any arguments passed to it This above code is executable in python 3 4 version

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This is a more abstract method     super self   class   self  baz arg

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Here is an example of using super      New-style classes inherit from object  or from another new-style class class Dog object        name          moves           def   init   self  name           self name   name      def moves setup self           self moves append  walk           self moves append  run        def get moves self           return self moves  class Superdog Dog         Let s try to append new fly ability to our Superdog     def moves setup self            Set default moves by calling method of parent class         super Superdog  self  moves setup           self moves append  fly    dog   Superdog  Freddy   print dog name   Freddy dog moves setup   print dog get moves       walk    run    fly      As you can see our Superdog has all moves defined in the base Dog class

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In this example cafec param is a base class  parent class  and abc is a child class  abc calls the AWC method in the base class   class cafec param       def   init   self precip pe awc nmonths            self precip   precip         self pe   pe         self awc   awc         self nmonths   nmonths      def AWC self            if self awc lt 254              Ss   self awc             Su   0             self Ss Ss         else              Ss   254  Su   self awc-254             self Ss Ss   Su            AWC   Ss   Su         return self Ss       def test self           return self Ss          return self Ss 4  class abc cafec param       def rr self           return self AWC     ee cafec param  re  34 56 2  dd abc  re  34 56 2  print dd rr    print ee AWC    print ee test      Output  56  56  56

[python] How to call a Parent Class's method from Child Class in Python?

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