As Set « Array « Ruby

1.Ruby can do several set operations on arrays
2.Difference (-) creates a new array, removing elements that appear in both arrays
3.Union (|) joins two arrays together, removing duplicates:
4.Computing Set Operations on Arrays: Union
5.Computing Set Operations on Arrays: Intersection
6.Computing Set Operations on Arrays: Difference
7.Set operation based on array
8.TypeError: cannot convert Set into Array
9.Set operation on array constant

10.Minus from one array
11.Exclude a list of natrual number