"Vincent Gulinao" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Sorry about that. I want something like: > > class foo: > > def __init__(self): > self.attr1 = None > def get_attr1(self): > if not self.attr1: > attr1 = <get value from DB, very expensive query> > self.attr1 = attr1 > return self.attr1 > > such that: > foo_instance = foo() > foo_instance.get_attr1() > foo_instance.attr1 > > gets the same value.
That looks like an ideal candidate for a "property". Using a property you can treat it as a data item but behind the scenes call a getter and setter method. In your case the getter would be the method you have above and the setter could write the new value to the database, if needed. Thus after defining the property attr1 you access like: foo_instance = Foo() print foo.attr1 # executes the getter foo.attr1 = 42 # executes the setter HTH, -- Alan Gauld Author of the Learn to Program web site http://www.freenetpages.co.uk/hp/alan.gauld _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
