Pierre wrote: > Hi, > > Sorry in advance, english is not my main language :/ > > I'd like to customize the result obtained by getattr on an object : if > the object has the requested property then return it BUT if the object > doesn't has actually this property return something else. > > In my case, I can't use getattr(object, property, default_value). > > I tried to write a class with a __getattr__ method and even a > __getattribute__ method but this doesn't do what I want.... > > Maybe I didn't correctly understand this : > http://docs.python.org/ref/attribute-access.html > > Here is a piece of my code : > ===================================== > class myclass: > """docstring""" > > a = 'aa' > b = 'bb' > > def __getattr___(self, ppt): > """getattr""" > if hasattr(self, ppt): > return self.ppt > else: > return "my custom computed result"
1) You have misspelled the method by adding a hard-to-spot third trailing underscore. 2) __getattr__ is called when normal lookup fails, so the condition evaluates always to False. > def __getattribute__(self, ppt): > """getattribute""" > if hasattr(self, ppt): > return self.ppt > else: > return "my custom computed result" 1) __getattribute__ is called for new-style classes only (those that inherit directly or indirectly from object). 2) Even if your class was new-style, this would enter an infinite loop because 'self.ppt' calls __getattribute__ again. George -- http://mail.python.org/mailman/listinfo/python-list
