On Mon, May 2, 2011 at 7:46 PM, Rita <rmorgan...@gmail.com> wrote: > Hello, > I was wondering if anyone has any documentation/recipes for implementing > complex data structures. For instance, if you had a dictionary with a list > inside a list inside a set.
Er, there's no special magic. The datatypes just nest normally. Pretty much the only thing to look out for is immutability/hashability. Dictionary keys and set elements should typically be immutable (and thus sensibly hashable). For this reason, tuples and frozensets are used instead of lists and non-frozen sets (respectively) in those situations (and in other cases where mutability should be disallowed). When creating a custom immutable type, one should override the __eq__(), __ne__(), and __hash__() special methods so that the type's instances can be used as dict keys and set elements. Your particular example combination doesn't work since it violates the aforementioned immutability rule. One should also be aware of the datatypes in the `collections` module, particularly `defaultdict`: http://docs.python.org/library/collections.html Cheers, Chris -- http://rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
