python - getslice deprecated in Python2.6, but still in use when subclassing tuple? -


consider following example, executed under python 2.6.6 (which i'm unfortunately stuck @ moment):

>>> class a: ...     def __getitem__(self, index): ...             print(type(index)) ...     def __getslice__(self, start, end): ...             print("don't call me, i'm deprecated") ... >>> = a() >>> a[3] <type 'int'> >>> a[3:3] <type 'slice'>

as should be, slicing call __getitem__. alter definition subclassing tuple:

>>> class b(tuple): ...     def __getitem__(self, index): ...             print(type(index)) ...     def __getslice__(self, start, end): ...             print("don't call me, i'm deprecated") ... >>> b = b() >>> b[3] <type 'int'> >>> b[3:] don't call me, i'm deprecated

why happening?

due historical reasons, __getslice__ in places still gets used builtin types. tuple, used [i:j] style syntax of slicing. see: http://bugs.python.org/issue2041 brief description , highlighted caveats in the getslice documentation


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