Steven D'Aprano writes: > Martin v. Löwis wrote: > >> It seems counter-productive to me to bother with an identity function > >> which doesn't meet that constraint. If id(x) == id(y) implies nothing > >> about x and y (they may, or may not, be the same object) then what's the > >> point? > > > > See James' explanation: it would be possible to use this as the > > foundation of an identity hash table. > > I'm afraid James' explanation didn't shed any light on the question to > me. It seems to me that Java's IdentityHashValue[sic -- I think the > correct function name is actually IdentityHashCode] is equivalent to > Python's hash(), not to Python's id(), and claiming it is related to > identity is misleading and confusing.
Not quite equivalent. Python's hash() obeys a certain additional constraint (that numeric values that compare equal have the same hash), and IdentityHashValue presumably won't work at all on numbers in Java (since they aren't objects). Bikeshedding aside, I have to agree with you: there's no point in calling such a function id() or IdentityAnything(). Everything you need to know (including both the fact that it could be an efficient way to search for a unique object, and the possible non-uniqueness of the object assigned that code) is contained in the word "hash". _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
