string 种的扩展方法

string 类的扩展方法
+ s1); //ten nine eight seven six five four three two one? TextBox1.Text = str;}

集合操作(Intersect、Except、Union):

去除重复(Distinct):

翻转(Reverse):

分组(GroupBy、GroupJoin):

protected void Button1_Click(object sender, EventArgs e){?   string str1 = "Asp.Net 3.5";?   string str2 = "";?   string r1 = string.Join("|", str1.DefaultIfEmpty());?   //A|s|p|.|N|e|t| |3|.|5?   string r2 = string.Join("|", str2.DefaultIfEmpty());?   //?   string r3 = string.Join("|", str2.DefaultIfEmpty('*')); //*?   TextBox1.Text = string.Concat(r1, "/n", r2, "/n", r3);}