Given a numpy array arr = np.array([1, 2, 3, 4, 5]) I need to construct a binary mask according to a (arbitrary, potentially long) list of values, i.e. given values = np.array([2, 4, 5]) mask should be mask = np.array([False, True, False, True, True]) So I want to avoid condition = (arr==2) or (arr==4) or (arr==5) mask = np.where(condition, arr) to get something like mask = np.in(values, arr) Or, if it is not possible, how to construct a condition from an arbitrary list of values to feed into np.where? Continue reading...