I noticed that np.bool_.__index__() gives a DeprecationWarning >>> np.bool_(True).__index__() __main__:1: DeprecationWarning: In future, it will be an error for 'np.bool_' scalars to be interpreted as an index 1
This is good, because booleans don't actually act like integers in indexing contexts. However, raw Python bools also allow __index__() >>> True.__index__() 1 A consequence of this is that NumPy slices allow booleans, as long as they are the Python type (if you use the NumPy bool_ type you get the deprecation warning). >>> a = np.arange(10) >>> a[True:] array([1, 2, 3, 4, 5, 6, 7, 8, 9]) Should this behavior also be considered deprecated? Presumably deprecating bool.__index__() in Python is a no-go, but it could be deprecated in NumPy contexts (in the pure Python collections, booleans don't have a special indexing meaning anyway). Interestingly, places that use a shape don't allow booleans (I guess they don't necessarily use __index__()?) >>> np.empty((True,)) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: an integer is required Aaron Meurer _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@python.org https://mail.python.org/mailman/listinfo/numpy-discussion
