On Oct 15, 12:14 am, Ole Streicher <ole-usenet-s...@gmx.net> wrote: > Hi, > > I am curious when one should implement a "__call__()" and when a > "__getitem__()" method. > > For example, I want to display functions and data in the same plot. For > a function, the natural interface would to be called as "f(x)", while > the natural interface for data would be "f[x]". On the other hand, > whether a certain data object is a function or a data table is just an > inner detail of the object (imagine f.e. a complex function that > contains a data table as cache), and there is no reason to distinguish > them by interface. > > So what is the reason that Python has separate __call__()/() and > __getitem__()/[] interfaces and what is the rule to choose between them?
It's just a language design decision. You can go either way, Python chose to be like C instead of Fortran or Ada. I've used both kinds of languages, and I prefer to have an external clue about the nature of the object I'm dealing with. However, I use many languages that don't distinguish between the two and it is not that big of a deal, and does have some small advantages. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
