a = numpy.array([0, 3, 0, 1, 0, 1, 2, 1, 0, 0, 0, 0, 1, 3, 4]) unique, counts = numpy.unique(a, return_counts=True) dict(zip(unique, counts)) {0: 7, 1: 4, 2: 1, 3: 2, 4: 1}