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Re: skipping __init__ and using exploiting a class member instead

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To be clear, my original post had a goof. 

So my original, de-goofed, idiom was


class Foo (object) :
    _lazy = None
    def foo(self, x) :
        self._lazy = self._lazy or self.get_something(x)
    def get_something(self, x) :
        # doesn't really matter, so long as it returns truthy result

and the new, improved idiom is 

class Foo (object) :
    def foo(self, x) :
        self._lazy = getattr(self, "_lazy", None) or self._get_something(x)
    def _get_something(self, x) :    
        # doesn't really matter, so long as it returns truthy result

I was laboring under some misconception that there was Python magic that allowed __init__ and only __init__ to add class attributes by setting their values. Good to know this piece of magic isn't part of Python, and thus lazy eval can be handled more cleanly than I originally thought. 

In other words, "Guido was here".

Thanks again

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skipping __init__ and using exploiting a class member instead Peter Cacioppi <peter.cacioppi@gmail.com> - 2013-10-19 14:44 -0700
  Re: skipping __init__ and using exploiting a class member instead Ned Batchelder <ned@nedbatchelder.com> - 2013-10-19 17:55 -0400
  Re: skipping __init__ and using exploiting a class member instead Peter Cacioppi <peter.cacioppi@gmail.com> - 2013-10-19 15:11 -0700
  Re: skipping __init__ and using exploiting a class member instead Robert Kern <robert.kern@gmail.com> - 2013-10-19 23:18 +0100
  Re: skipping __init__ and using exploiting a class member instead Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-19 22:30 +0000
  Re: skipping __init__ and using exploiting a class member instead Peter Cacioppi <peter.cacioppi@gmail.com> - 2013-10-19 17:07 -0700
  Re: skipping __init__ and using exploiting a class member instead Peter Cacioppi <peter.cacioppi@gmail.com> - 2013-10-19 17:42 -0700
    Re: skipping __init__ and using exploiting a class member instead Ned Batchelder <ned@nedbatchelder.com> - 2013-10-19 21:13 -0400
    Detecting whether a value was passed for a parameter (was: skipping __init__ and using exploiting a class member instead) Ben Finney <ben+python@benfinney.id.au> - 2013-10-20 22:50 +1100
  Re: skipping __init__ and using exploiting a class member instead Peter Cacioppi <peter.cacioppi@gmail.com> - 2013-10-20 00:09 -0700
    Re: skipping __init__ and using exploiting a class member instead Roy Smith <roy@panix.com> - 2013-10-20 08:55 -0400
    Re: skipping __init__ and using exploiting a class member instead Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-20 14:16 +0100
  Re: skipping __init__ and using exploiting a class member instead Peter Cacioppi <peter.cacioppi@gmail.com> - 2013-10-20 01:46 -0700
  Re: skipping __init__ and using exploiting a class member instead Devin Jeanpierre <jeanpierreda@gmail.com> - 2013-10-20 07:27 -0700
  Re: skipping __init__ and using exploiting a class member instead Peter Cacioppi <peter.cacioppi@gmail.com> - 2013-10-20 10:57 -0700
    Re: skipping __init__ and using exploiting a class member instead Roy Smith <roy@panix.com> - 2013-10-20 16:44 -0400
    Re: skipping __init__ and using exploiting a class member instead Chris Angelico <rosuav@gmail.com> - 2013-10-21 07:57 +1100
      Re: skipping __init__ and using exploiting a class member instead Peter Cacioppi <peter.cacioppi@gmail.com> - 2013-10-20 14:34 -0700
        Re: skipping __init__ and using exploiting a class member instead Roy Smith <roy@panix.com> - 2013-10-20 18:31 -0400
          Re: skipping __init__ and using exploiting a class member instead Ben Finney <ben+python@benfinney.id.au> - 2013-10-21 10:55 +1100
            Re: skipping __init__ and using exploiting a class member instead Neil Cerutti <neilc@norwich.edu> - 2013-10-21 18:47 +0000
  Re: skipping __init__ and using exploiting a class member instead Peter Cacioppi <peter.cacioppi@gmail.com> - 2013-10-20 21:30 -0700
  Re: skipping __init__ and using exploiting a class member instead Peter Cacioppi <peter.cacioppi@gmail.com> - 2013-10-20 21:31 -0700
    Re: skipping __init__ and using exploiting a class member instead feedthetroll@gmx.de - 2013-10-21 00:16 -0700

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