define

[Alex Martelli]

<posted & mailed>

Turhan Ozen wrote:

> __getattr__ is getting into infinite loop. I just copied the code. Could
> you please help me how to avoid this?

Sure -- there were a couple of booboos (which is why I warned that the
code was untested;-), easy to fix -- so, here's a working script:


class list_with_names(list):

    __names = {}

    def __init__(self, names):
        list.__init__(self, len(names)*[None])
        self.__names = {}
        for i, name in enumerate(names):
            self.__names[name] = i

    def __getattr__(self, name):
        try: return self[self.__names[name]]
        except KeyError: raise AttributeError

    def __setattr__(self, name, value):
        try: self[self.__names[name]] = value
        except LookupError: object.__setattr__(self, name, value)


if __name__ == '__main__':
    # minimal self-test only if run as main script
    # e.g. a list of 5 items
    x = list_with_names(
        'aname another yetanother onemore andthistoo'.split())

    x[1] = 23
    print x.another

    print x


This prints:

23
[None, 23, None, None, None]


Alex