Check if all sides of a multidimensional numpy array are arrays of zeros

Question

An n-dimensional array has 2n sides (a 1-dimensional array has 2 endpoints; a 2-dimensional array has 4 sides or edges; a 3-dimensional array has 6 2-dimensional faces; a 4-dime

Answer 1

Here's how you can do it:

assert(all(np.all(np.take(x, index, axis=axis) == 0)
           for axis in range(x.ndim)
           for index in (0, -1)))

np.take does the same thing as "fancy" indexing.