Martin v. Löwis wrote: > It follows from what is documented. set(<iterable object>) creates a > set that contains all elements in the iterable object: > http://docs.python.org/lib/built-in-funcs.html#l2h-63 > Now, is a dictionary an iterable object? Yes, it is: > http://www.python.org/peps/pep-0234.html > Together, this gives the property I demonstrated.
You need to know a third thing, namely that as an iterable object, a dictionary returns the keys only, not the key/value tuples which would also make some sense. If it had been designed that way, you could write for k, v in d: print k, v instead of: for k in d: print k, d[k] What I wanted to say is that the doco could mention this possibility to get the keys as a set at the place where it explains the keys() method. -- Christoph -- http://mail.python.org/mailman/listinfo/python-list