Set routines

Making proper sets

unique(ar[, return_index, return_inverse, ...])	Find the unique elements of an array.
unique_all(x, /)	Find unique values and their indices, inverse indices, and counts.
unique_counts(x, /)	Find unique values and their occurrence counts.
unique_inverse(x, /)	Find unique values and the indices needed to reconstruct the input.
unique_values(x, /)	Find the unique values in an array.
in1d(ar1, ar2[, assume_unique, invert, kind])	Test whether each element of this 1-D array is also present in a second array.
isin(element, test_elements[, ...])	Calculates element in test_elements, broadcasting over element only.