LINQ 典型 字符串匹配
请教达人: 找出B1在A1中(以逗号分隔的)完全匹配的字符串结果：

string  A1 = "abc,efg,hik,lmn,opq"; 
string  B1= "efg,d3l,opq,LMn";

想要结果:

输出:efg,opq   

说明:(因为B1中只有efg与opq和A1中完全匹配)

用LINQ如何实现呢?
[解决办法]

            string A1 = "abc,efg,hik,lmn,opq";
            string B1 = "efg,d3l,opq,LMn";
            string[] arr = A1.Split(',').Select(x => x).Where(y => B1.Split(',').Contains(y)).ToArray();

[解决办法]
var result = A1.Split(',').Intersect(A2.Split(','));
[解决办法]

 string A1 = "abc,efg,hik,lmn,opq";
            string B1 = "efg,d3l,opq,LMn";
            string C1 = string.Join(",", A1.Split(',').Intersect(B1.Split(',')).ToArray());