using System; using System.Text.RegularExpressions; public class Test { public static void Main() { string input = "ID03I010102010210AEMPD4677EID03I020102020208L8159734ID03I030102030210IPS1406974PT03T010109981815938030202PT03T0201109899488666030201PT03T0301109818159381030203PT03T040112919818159381030201"; string delimiter = "ID03I0"; string pattern = string.Format("(?<=.)(?={0})", delimiter); string[] result = Regex.Split(input, pattern); foreach (var line in result) Console.WriteLine(line); } }