using System;
using System.Text.RegularExpressions;

namespace RegExApplication
{
    class Program
    {

        static void Main(string[] args)
        {
            //1、純數字提取
            Console.WriteLine("純數字提取:" + Regex.Replace("abAB 001 2dd", @"[^0-9]+", ""));

            //2、帶有小數點數字提取
            Console.WriteLine("
 
帶有小數點數字提取：" + Regex.Replace("abA2d1.255d", @"[^\d.\d]", ""));

            //3、大寫字母提取
            Console.WriteLine("大寫字母提取:" + Regex.Replace("abAB 001 2dd", @"[^A-Z]+", ""));

            //4、小寫字母提取
            Console.WriteLine("小寫字母提取:" + Regex.Replace("abAB 001 2dd", @"[^a-z]+", ""));

            //5、數字或大小寫字母提取
 

            Console.WriteLine("數字或大小寫字母提取:" + Regex.Replace("abAB $%001 &2%dd", @"[^A-Za-z0-9]+", ""));

            
            Console.ReadKey();
        }
    }
}

轉：https://blog.csdn.net/yyq3871584/article/details/115044541