Pads a list on both sides with a filler value (`0` by default).
ArrayPad[array, m]
ArrayPad[array, m, padding]
ArrayPad[array, {m, n}, …]
ArrayPad[array, {{m1, n1}, {m2, n2}, …}, …]
ArrayPad[{1, 2, 3}, 2]
→ {0, 0, 1, 2, 3, 0, 0}ArrayPad[{1, 2, 3}, 2, 0]
→ {0, 0, 1, 2, 3, 0, 0}