集合的并集是合并集合的项，如下图所示：
Listls1 = new List () { 1,2,3,5,7,9 }; List ls2 = new List () { 2,4,6,8,9,10}; IEnumerable unionLs = ls1.Union(ls2);foreach (int item in unionLs) { Console.Write("{0}\t", item); }
集合的交集是取集合的共同的项，如下图所示：
Listls1 = new List () { 1,2,3,5,7,9 }; List ls2 = new List () { 2,4,6,8,9,10}; IEnumerable intersectLs = ls1.Intersect(ls2);foreach (int item in intersectLs) { Console.Write("{0}\t",item); }
集合的差集是取在该集合中而不在另一集合中的所有的项，如下图所示：
Listls1 = new List () { 1,2,3,5,7,9 }; List ls2 = new List () { 2,4,6,8,9,10}; IEnumerable exceptLs = ls1.Except(ls2);foreach (int item in exceptLs) { Console.Write("{0}\t", item); }
