numpy.setdiff1d(ar1, ar2, assume_unique=False)[source]

Find the set difference of two arrays.

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

Parameters :

ar1 : array_like

Input array.

ar2 : array_like

Input comparison array.

assume_unique : bool

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

Returns :

setdiff1d : ndarray

Sorted 1D array of values in ar1 that are not in ar2.

See also

Module with a number of other functions for performing set operations on arrays.


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

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