numpy.setdiff1d

numpy.setdiff1d(ar1, ar2, assume_unique=False)

Find the set difference of two arrays.

Return the unique values in ar1 that are not in ar2.

Parameters:

ar1array_like

Input array.

ar2array_like

Input comparison array.

assume_uniquebool

If True, the input arrays are both assumed to be unique, which can speed up the calculation. Default is False.

Returns:

setdiff1dndarray

1D array of values in ar1 that are not in ar2. The result is sorted when assume_unique=False, but otherwise only sorted if the input is sorted.

Examples

>>> a = np.array([1, 2, 3, 2, 4, 1])
>>> b = np.array([3, 4, 5, 6])
>>> np.setdiff1d(a, b)
array([1, 2])