changing __getattr__ dynamically

Satchidanand Haridas sharidas at zeomega.com
Wed Jul 28 11:21:55 CEST 2004


Dan Bentley wrote:

>class foo(object):
>  def __getattr__(self, name):
>    return 42
>
>def e(self, name):
>  return 2.7
>
>bar = foo()
>print bar.baz
>bar.__getattr__ = e
>print bar.baz
>
>I'd expect this to print:
>42
>2.7
>
>But instead it prints:
>42
>42
>
>Is there a way to change the actual __getattr__ used at runtime?
>
>-D"python 2.3.3 on Mac OS X 10.3.4"an
>  
>

The following code will do so:

<code>

class foo(object):

    def __getattr__(self, name):
        if 'attrFunc' in self.__dict__:
            return self.__dict__['attrFunc'](name)
        else:
            return 42
           
    def __setattr__(self,name,value):
        self.__dict__[name] = value

    def e(self,name):
        return 27

bar = foo()
print bar.baz
bar.attrFunc = bar.e
print bar.baz

</code>

Regards,
Satchit

----
Satchidanand Haridas (sharidas at zeomega dot com)

ZeOmega (www.zeomega.com)
Open  Minds' Open Solutions

#20,Rajalakshmi Plaza,
South End Road,
Basavanagudi,
Bangalore-560 004, India








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