一分钟学会（一）：.NET之正则表达式

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Text.RegularExpressions;
namespace demo
{
    class Program
    {
        static void Main(string[] args)
        {
            Test6();

            Console.ReadLine();
        }


        //1.查找
        static void Test1()
        {
            Console.WriteLine("=========Match方法匹配第一个===========");
            Regex regex = new Regex(@"\d{3}"); //@ 表示不用进行转义 \在.NET中是转义符 此表达式等同于 \\d{3}
            Match m = regex.Match("this is an apple 123 456 9999");
            Console.WriteLine(m);

            Console.WriteLine("=========Matches方法匹配所有===========");
            MatchCollection matches = regex.Matches("this is an apple 123 456 9999");
            foreach(Match match in matches)
            {
                Console.WriteLine(match);
            }

            Console.WriteLine("=========Matches方法匹配所有===========");
            bool result = regex.IsMatch("this is an apple 123 456 9999");
            Console.WriteLine(result);
        }

        //2.替换操作
        static void Test2()
        {
            //替换所有匹配项
            Regex regex = new Regex("apple");
            string result = regex.Replace("this is an apple,apple,apple", "苹果");
            Console.Write(result);
        }

        //3.使用委托
        static void Test3() 
        {
            string result = Regex.Replace("1 2 3 4 5",@"\d+", new MatchEvaluator(
                delegate(Match match) {//匿名方法
                    return "0" + match.Value;
                }
            ),RegexOptions.IgnoreCase|RegexOptions.Singleline);
            //最后一个参数匹配模式 可选
            Console.WriteLine(result);
        }

        //4.$number 使用表达式替换匹配结果中的 number 组  $1表示组1匹配的结果
        static void Test4()
        {
            string result = Regex.Replace("1 2 3 12 13", @"(\d)(\d)", "A$1");
            Console.WriteLine(result);
        }

        //5.${name} 使用表达式替换匹配结果中的 name 组  ${name}表示组名为name匹配的结果 ?<name> 给改组命名为name
        static void Test5() {
            string result = Regex.Replace("1 2 3 12 13", @"(\d)(?<name>\d)", "A${name}");
            Console.WriteLine(result);
        
        }
        //补充
        //$$ $转义符
        //$& 替换整个匹配
        //$^ 替换匹配前的字符
        //$‘ 替换匹配后的字符
        //$+ 替换最后匹配的组
        //$_ 替换整个字符串
        //(?#这个是注释)  正则内联注释语法 (?#注释)

        //6.1分组
        static void Test6() 
        {
            string s = "2005-2-21";
            Regex reg = new Regex(@"(?<y>\d{4})-(?<m>\d{1,2})-(?<d>\d{1,2})", RegexOptions.Compiled);
            Match match = reg.Match(s);

            int year = int.Parse(match.Groups["y"].Value);
            int month = int.Parse(match.Groups["m"].Value);
            int day = int.Parse(match.Groups["d"].Value);

            DateTime time = new DateTime(year, month, day);
            Console.WriteLine(time);
            Console.ReadLine();

            //DateTime.Parse(s);
        }

        //6.2
        static void Test7()
        {
            string s = "2005-2-21";
            Regex reg = new Regex(@"(\d{4})-(\d{1,2})-(\d{1,2})", RegexOptions.Compiled);
            Match match = reg.Match(s);

            int year = int.Parse(match.Groups[1].Value);
            int month = int.Parse(match.Groups[2].Value);
            int day = int.Parse(match.Groups[3].Value);

            DateTime time = new DateTime(year, month, day);
            Console.WriteLine(time);
            Console.ReadLine();
        }

        //6.3
        static void Test8()
        {
            string s = "2005-2-21";
            Regex reg = new Regex(@"(?<2>\d{4})-(?<1>\d{1,2})-(?<3>\d{1,2})", RegexOptions.Compiled);
            Match match = reg.Match(s);

            int year = int.Parse(match.Groups[2].Value);
            int month = int.Parse(match.Groups[1].Value);
            int day = int.Parse(match.Groups[3].Value);

            DateTime time = new DateTime(year, month, day);
            Console.WriteLine(time);
            Console.ReadLine();
        }

    }
}