New submission from Santoso Wijaya: The reference doc for Python data model says that __getslice__ is deprecated [1], and that __getitem__ should be used instead:
""" Deprecated since version 2.0: Support slice objects as parameters to the __getitem__() method. (However, built-in types in CPython currently still implement __getslice__(). Therefore, you have to override it in derived classes when implementing slicing.) """ But I'm getting the following behavior when I try it myself. Is there something I'm missing? $ python Python 2.7.6 (default, Mar 22 2014, 22:59:56) [GCC 4.8.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> class tup(object): ... def __getitem__(self, i): ... if i == 0: return 0 ... if i == 1: return 1 ... KeyboardInterrupt >>> class tup(object): ... def __getitem__(self, i): ... if i in (0, 1): return i ... else: raise IndexError() ... def __len__(self): ... return 2 ... >>> t = tup() >>> len(t) 2 >>> t[0], t[1] (0, 1) >>> t[:2] Traceback (most recent call last): File "<stdin>", line 1, in <module> File "<stdin>", line 4, in __getitem__ IndexError >>> t[:1] Traceback (most recent call last): File "<stdin>", line 1, in <module> File "<stdin>", line 4, in __getitem__ IndexError [1] https://docs.python.org/2/reference/datamodel.html#object.__getslice__ ---------- components: Library (Lib) messages: 219326 nosy: santa4nt priority: normal severity: normal status: open title: Is __getitem__ and __len__ implementations enough to make a user-defined class sliceable? type: behavior versions: Python 2.7 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue21598> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
