On Mon, Jan 17, 2022 at 10:14 AM Paul Moore <[email protected]> wrote: > > On Sun, 16 Jan 2022 at 22:55, Steven D'Aprano <[email protected]> wrote: > > >>> def f(): > > ... return frozenset({1, 2, 3}) > > ... > > >>> a = f.__code__.co_consts[1] > > >>> a > > frozenset({1, 2, 3}) > > >>> b = f() > > >>> assert a == b > > >>> a is b > > False > > > > Each time you call the function, you get a distinct frozenset object. > > I may just be reiterating your point here (if I am, I'm sorry - I'm > not completely sure), but isn't that required by the definition of the > frozenset function. You're calling frozenset(), which is defined to > "Return a new frozenset object, optionally with elements taken from > iterable". The iterable is the (non-frozen) set {1, 2, 3}.
Where is that definition? According to help(frozenset), it will "[b]uild an immutable unordered collection of unique elements", so it doesn't necessarily have to be a brand new object. With mutables, it does have to return a new one every time (list(x) will give you a shallow copy of x even if it's already a list), but with immutables, it's okay to return the same one (str and tuple will return self). ChrisA _______________________________________________ Python-ideas mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/[email protected]/message/G23OMELEM6KFNTB36ZIBA23K2XXUWJLU/ Code of Conduct: http://python.org/psf/codeofconduct/
