using System; using System.Data; using System.Text.RegularExpressions; class Class1{ static void Main(string[] args){ string IsNotNum = "111west"; string IsNum = " +111 "; string IsFloat = " 23.11 "; string IsExp = " +23 e+11 "; Console.WriteLine(GetNumberFromStr(IsNum)); // +111 Console.WriteLine(GetNumberFromStr(IsNotNum)); // Console.WriteLine(GetNumberFromStr(IsFloat)); // 23.11 Console.WriteLine(GetNumberFromStr(IsExp)); // } public static string GetNumberFromStr(string str) { str = str.Trim(); Match m = Regex.Match(str, @"^[+-]?d*.?[Ee]?[+-]?d*$"); return (m.Value); } }