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Re: Python getters and setters

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On 17/08/2013 17:53, Fernando Saldanha wrote:
> I am new to Python.
>
> I understand that it is "unpythonic" to write getters and setters, and that property() can be used if necessary.
>
> This deals with the case of attributes, but there are other kinds of information available within a class.
>
> Suppose my class contains an attribute called "data" that can potentially provide a lot of information that will be needed by class users. I have two options:
>
> 1) For each piece of information within data (e.g., length) I write a method that retrieves that information:
>
>      def data_length(self):
>          return len(self.data)
>
> 2) I do not create such a method. Users that are interested in that information will have to write len(obj.data), where obj is a previously instantiated object of my class.
>
> Which one of the two alternatives fits better with the Python philosophy? The first alternative is more work for me, creates a "heavier" class and may have slower performance, but makes things easier for the user and is more implementation independent.
>
If the attribute is public, i.e. the user is expected to write obj.data, 
then
len(obj.data) is the right way to get its length.

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Python getters and setters Fernando Saldanha <fsaldan1@gmail.com> - 2013-08-17 09:53 -0700
  Re: Python getters and setters MRAB <python@mrabarnett.plus.com> - 2013-08-17 18:10 +0100
  Re: Python getters and setters Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-08-17 17:18 +0000
    Re: Python getters and setters Tim Chase <python.list@tim.thechases.com> - 2013-08-17 12:31 -0500
    Re: Python getters and setters Irmen de Jong <irmen.NOSPAM@xs4all.nl> - 2013-08-18 00:52 +0200
      Re: Python getters and setters Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-08-17 23:40 +0000
        Re: Python getters and setters Chris Angelico <rosuav@gmail.com> - 2013-08-18 02:07 +0100
  Re: Python getters and setters Fernando Saldanha <fsaldan1@gmail.com> - 2013-08-17 22:26 -0700

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