two array
A) 1, 2, 3, 4, 5, 6
B) 4, 6, 9

how can to have an array
C) 4, 6
all the B's values that have value in A

and
an array
D) 1, 2, 3, 4, 5, 6, 9
a simple union of A + B with no duplicates values