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Re: Accessing container's methods

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On 12/7/2015 1:10 PM, Tony van der Hoff wrote:
> Hi,
>
> I have a class A, containing embedded embedded classes, which need to
> access methods from A.
> .
> A highly contrived example, where I'm setting up an outer class in a
> Has-a relationship, containing a number of Actors. The inner class needs
> to access a method of the outer class; here the method get_name.
>
> I don't really want to make Actor a sub-class (is-a; it isn't) of Monty;
> that would raise all sorts of other problems.
>
> Can anyone please advise me on how to achieve this magic?
>
> # define the outer class
> class Monty:
>    def __init__( self, names ):
>      self.actors = []
>
>      i = 0
>      for n in names:
>        self.actors.append( Actor( n, i ) )
>        i += 1    # here is a case for python supporting post-increment!

This is actually a case for using enumerate:
   for i, name in enumerate(names):

>
>    def count_actors( self ):
>      return len( self.actors )
>
>    def list_actors( self ):
>      h=[]
>      for n in self.actors:
>        h.append( n.get_name() )
>      return h

return list(self.actors)  # or perhaps even faster
return self.actors[:]

> # define the inner class
> class Actor:
>    def __init__ ( self, name, id ):
>      self.name = name
>      self.id = id

Tkinter, and I presume tk, works by creating circular references.
widgets get a reference to a master widget, and container get a 
reference to widgets that are placed (or packed or gridded) therein. 
Widgets have an explicit .destroy method (inherited from tcl/tk) to undo 
the circularity.  It works, but it is not completely without problems.

-- 
Terry Jan Reedy

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Thread

Accessing container's methods Tony van der Hoff <tony@vanderhoff.org> - 2015-12-07 18:10 +0000
  Re: Accessing container's methods Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2015-12-07 18:21 +0000
  Re: Accessing container's methods Michael Torrie <torriem@gmail.com> - 2015-12-07 11:36 -0700
    Re: Accessing container's methods Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-12-07 20:03 +0100
  Re: Accessing container's methods Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-12-07 19:46 +0100
  Re: Accessing container's methods Peter Otten <__peter__@web.de> - 2015-12-07 19:59 +0100
  Re: Accessing container's methods Ian Kelly <ian.g.kelly@gmail.com> - 2015-12-07 12:33 -0700
  Re: Accessing container's methods Terry Reedy <tjreedy@udel.edu> - 2015-12-07 16:38 -0500
  Re: Accessing container's methods Chris Angelico <rosuav@gmail.com> - 2015-12-08 09:02 +1100
  Re: Accessing container's methods Erik <python@lucidity.plus.com> - 2015-12-07 23:47 +0000
    Re: Accessing container's methods Tony van der Hoff <tony@vanderhoff.org> - 2015-12-08 12:35 +0000
    Re: Accessing container's methods [solved] Tony van der Hoff <tony@vanderhoff.org> - 2015-12-08 13:46 +0000
    Re: Accessing container's methods Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-12-08 20:02 +0100
      Re: Accessing container's methods Vincent Vande Vyvre <vincent.vande.vyvre@telenet.be> - 2015-12-08 20:54 +0100
        Re: Accessing container's methods Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-12-08 23:51 +0100
      Re: Accessing container's methods Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-12-08 20:30 +0000
        Re: Accessing container's methods Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-12-08 23:52 +0100
          Re: Accessing container's methods Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-12-08 22:59 +0000
      Re: Accessing container's methods Erik <python@lucidity.plus.com> - 2015-12-08 22:37 +0000
      Re: Accessing container's methods Ian Kelly <ian.g.kelly@gmail.com> - 2015-12-08 16:41 -0700
      Re: Accessing container's methods Chris Angelico <rosuav@gmail.com> - 2015-12-09 12:04 +1100

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