Replace elements by the commonest value in their neighborhood
CommonestFilter[data, r]
CommonestFilter[data, {r1, r2, …}]
CommonestFilter[{0, 1, -1, 1, 2, 1, 3, 3, 3, 1}, 1]
→ {0, 1, 1, 1, 1, 1, 3, 3, 3, 1}CommonestFilter[ {a, b, b, c, c, c, d, d, e}, 2]
→ {b, b, b, c, c, c, d, d, d}