I started an enhancement request in the Github bug tracker at https://github.com/numpy/numpy/issues/8331 , but Jaime Frio recommended I bring it to the mailing list.
`in1d` takes two arrays, `ar1` and `ar2`, and returns a 1d array with the same number of elements as `ar1`. The logical extension would be a function that does the same thing but returns a (possibly multi-dimensional) array of the same shape as `ar1`. The code already has a comment suggesting this could be done (see https://github.com/numpy/numpy /blob/master/numpy/lib/arraysetops.py#L444 ). I agree that changing the behavior of the existing function isn't an option, since it would break backwards compatability. I'm not sure adding an option keep_shape is good, since the name of the function ("1d") wouldn't match what it does (returns an array that might not be 1d). I think a new function is the way to go. This would be it, more or less: def items_in(ar1, ar2, **kwargs): return np.in1d(ar1, ar2, **kwargs).reshape(ar1.shape) Questions I have are: * Function name? I was thinking something like `items_in` or `item_in`: the function returns whether each item in `ar1` is in `ar2`. Is "item" or "element" the right term here? * Are there any other changes that need to happen in arraysetops.py? Or other files? I ask this because although the file says "Set operations for 1D numeric arrays" right at the top, it's growing increasingly not 1D: `unique` recently changed to operate on multidimensional arrays, and I'm proposing a multidimensional version of `in1d`. `ediff1d` could probably be tweaked into a version that operates along an axis the same way unique does now, fwiw. Mostly I want to know if I should put my code changes in this file or somewhere else. Thanks, -brsr
_______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org https://mail.scipy.org/mailman/listinfo/numpy-discussion
