string

       string s = "取子字符串";
         string s1 = s.Substring(2, 2);//Substring得到子字符串或字符
         Console.WriteLine(s1);
         string s2 = s.Remove(0, 2);//Remove移除字符
         Console.WriteLine( s2);

         string a = "計算機科學";
         string a1 = a.Insert(3, "軟件");//Insert插入字符串
         Console.WriteLine(a1);
         string a2 = a.Replace("計算機", "軟件");//Replace字符串替換
         Console.WriteLine(a2);
         char[] a3 = a.ToCharArray(0, a.Length);//ToCharArray把string轉換爲字符數組
         Console.WriteLine(a3.Length);

         string z = "ASDasd";
         string z1 = z.ToLower();//ToLower把字符轉換爲小寫
         Console.WriteLine(z1);
         string z2 = z.ToUpper();//ToUpper把字符轉換爲大寫
         Console.WriteLine(z2);

         string x = "  A  zxc  ";
         x = x.Trim();//Trim刪除字符串頭部及尾部的空格
         Console.WriteLine(x);