正则表达式列子

ゝ一世哀愁。 2022-05-10 01:28 174阅读 0赞

基于过程：

using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Text.RegularExpressions;
    using System.Threading.Tasks;
    
    namespace RegexpTest
    {
        class Program
        {
            static void Main(string[] args)
            {
                string text = "the quick red fox jumped over the lazy brown dog.";
                Console.WriteLine("text=[" + text + "]");
                string result = "";
                string pattern = @"\w+|\W+";
                foreach (Match m in Regex.Matches(text, pattern)) //Match: 一次表达式的匹配结果，由Group继承而来；Matches: 返回一系列的Match的方法； 
                {
                    // 取得匹配的字符串 
                    string x = m.ToString();
                    // 如果第一个字符是小写 
                    if (char.IsLower(x[0]))
                        // 变成大写 
                        x = char.ToUpper(x[0]) + x.Substring(1, x.Length - 1);
                    // 收集所有的字符 
                    result += x;
                }
                Console.WriteLine("result=[" + result + "]");
                Console.ReadKey();
    
                
            }
        }
    }

基于表达式方法：

static string CapText(Match m)
            {
                //取得匹配的字符串 
                string x = m.ToString();
                // 如果第一个字符是小写 
                if (char.IsLower(x[0]))
                 // 转换为大写 
                return char.ToUpper(x[0]) + x.Substring(1, x.Length - 1);
                return x;
            }
    
            static void Main()
            {
                 string text = "the quick red fox jumped over the lazy brown dog."; 
                Console.WriteLine("text=[" + text + "]");
                string pattern = @"\w+";
                string result = Regex.Replace(text, pattern, new MatchEvaluator(CapText));
                Console.WriteLine("result=[" + result + "]");
                Console.ReadKey();
            }

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 <td>常用表达式 　　为了能够更好地理解如何在C#环境中使用规则表达式，我写出一些对你来说可能有用的规则表达式，这些表达式在其他的环境中都被使用过，希望能够对你有所帮助。&nbsp; &nbsp;&nbsp; 罗马数字 string p1 = "^m*(d?c{0,3}|c[dm])" + "(l?x{0,3}|x[lc])(v?i{0,3}|i[vx])$"; &nbsp;&nbsp; &nbsp; 　　string t1 = "vii"; &nbsp;&nbsp; &nbsp; 　　Match m1 = Regex.Match(t1, p1);&nbsp; &nbsp;&nbsp;&nbsp; 交换前二个单词 string t2 = "the quick brown fox"; &nbsp;&nbsp; &nbsp; 　　string p2 = @"(\S+)(\s+)(\S+)"; &nbsp;&nbsp; &nbsp; 　　Regex x2 = new Regex(p2); &nbsp;&nbsp; &nbsp; 　　string r2 = x2.Replace(t2, "$3$2$1", 1); &nbsp;&nbsp;&nbsp; 关健字=值 string t3 = "myval = 3"; &nbsp;&nbsp; &nbsp; 　　string p3 = @"(\w+)\s*=\s*(.*)\s*$"; &nbsp;&nbsp; &nbsp; 　　Match m3 = Regex.Match(t3, p3); &nbsp;&nbsp;&nbsp; 实现每行80个字符 string t4 = "********************" &nbsp;&nbsp; &nbsp; 　　 + "******************************" &nbsp;&nbsp; &nbsp; 　　 + "******************************"; &nbsp;&nbsp; &nbsp; 　　string p4 = ".{80,}"; &nbsp;&nbsp; &nbsp; 　　Match m4 = Regex.Match(t4, p4); &nbsp;&nbsp;&nbsp; 月/日/年 小时:分:秒的时间格式 string t5 = "01/01/01 16:10:01"; &nbsp;&nbsp; &nbsp; 　　string p5 = @"(\d+)/(\d+)/(\d+) (\d+):(\d+):(\d+)"; &nbsp;&nbsp; &nbsp; 　　Match m5 = Regex.Match(t5, p5); &nbsp;&nbsp;&nbsp; 改变目录（仅适用于Windows平台） string t6 = @"C:\Documents and Settings\user1\Desktop\"; &nbsp;&nbsp; &nbsp; string r6 = Regex.Replace(t6,@"\\user1\\", @"\\user2\\"); &nbsp;&nbsp;&nbsp; 扩展16位转义符 string t7 = "%41"; // capital A &nbsp;&nbsp; &nbsp; 　　string p7 = "%([0-9A-Fa-f][0-9A-Fa-f])"; &nbsp;&nbsp; &nbsp; 　　string r7 = Regex.Replace(t7, p7, HexConvert);&nbsp; &nbsp;&nbsp;&nbsp; 删除C语言中的注释（有待完善） string t8 = @" &nbsp;&nbsp; &nbsp; 　　/* &nbsp;&nbsp; &nbsp; 　　 * 传统风格的注释 &nbsp;&nbsp; &nbsp; 　　 */ &nbsp;&nbsp; &nbsp; 　　"; &nbsp;&nbsp; &nbsp; 　　string p8 = @" &nbsp;&nbsp; &nbsp; 　　 /\* # 匹配注释开始的定界符 &nbsp;&nbsp; &nbsp; 　　 .*? # 匹配注释 &nbsp;&nbsp; &nbsp; 　　 \*/ # 匹配注释结束定界符 &nbsp;&nbsp; &nbsp; 　　"; &nbsp;&nbsp; &nbsp; 　　string r8 = Regex.Replace(t8, p8, "", "xs");&nbsp; &nbsp;&nbsp;&nbsp; 删除字符串中开始和结束处的空格 string t9a = " leading"; &nbsp;&nbsp; &nbsp; 　　string p9a = @"^\s+"; &nbsp;&nbsp; &nbsp; 　　string r9a = Regex.Replace(t9a, p9a, ""); &nbsp;&nbsp; &nbsp; 　　string t9b = "trailing "; &nbsp;&nbsp; &nbsp; 　　string p9b = @"\s+$"; &nbsp;&nbsp; &nbsp; 　　string r9b = Regex.Replace(t9b, p9b, "");&nbsp; &nbsp;&nbsp;&nbsp; 在字符\后添加字符n，使之成为真正的新行 string t10 = @"\ntest\n"; &nbsp;&nbsp; &nbsp; 　　string r10 = Regex.Replace(t10, @"\\n", "\n");&nbsp; &nbsp;&nbsp;&nbsp; 转换IP地址 string t11 = "55.54.53.52"; &nbsp;&nbsp; &nbsp; 　　string p11 = "^" + &nbsp;&nbsp; &nbsp; 　　 @"([01]?\d\d|2[0-4]\d|25[0-5])\." + &nbsp;&nbsp; &nbsp; 　　 @"([01]?\d\d|2[0-4]\d|25[0-5])\." + &nbsp;&nbsp; &nbsp; 　　 @"([01]?\d\d|2[0-4]\d|25[0-5])\." + &nbsp;&nbsp; &nbsp; 　　 @"([01]?\d\d|2[0-4]\d|25[0-5])" + &nbsp;&nbsp; &nbsp; 　　 "$"; &nbsp;&nbsp; &nbsp; 　　Match m11 = Regex.Match(t11, p11);&nbsp; &nbsp;&nbsp;&nbsp; 删除文件名包含的路径 string t12 = @"c:\file.txt"; &nbsp;&nbsp; &nbsp; 　　string p12 = @"^.*\\"; &nbsp;&nbsp; &nbsp; 　　string r12 = Regex.Replace(t12, p12, "");&nbsp; &nbsp;&nbsp;&nbsp; 联接多行字符串中的行 string t13 = @"this is &nbsp;&nbsp; &nbsp; 　　a split line"; &nbsp;&nbsp; &nbsp; 　　string p13 = @"\s*\r?\n\s*"; &nbsp;&nbsp; &nbsp; 　　string r13 = Regex.Replace(t13, p13, " "); &nbsp;&nbsp;&nbsp; 提取字符串中的所有数字 string t14 = @" &nbsp;&nbsp; &nbsp; 　　test 1 &nbsp;&nbsp; &nbsp; 　　test 2.3 &nbsp;&nbsp; &nbsp; 　　test 47 &nbsp;&nbsp; &nbsp; 　　"; &nbsp;&nbsp; &nbsp; 　　string p14 = @"(\d+\.?\d*|\.\d+)"; &nbsp;&nbsp; &nbsp; 　　MatchCollection mc14 = Regex.Matches(t14, p14);&nbsp; &nbsp;&nbsp;&nbsp; 找出所有的大写字母 string t15 = "This IS a Test OF ALL Caps"; &nbsp;&nbsp; &nbsp; 　　string p15 = @"(\b[^\Wa-z0-9_]+\b)"; &nbsp;&nbsp; &nbsp; 　　MatchCollection mc15 = Regex.Matches(t15, p15);&nbsp; &nbsp;&nbsp;&nbsp; 找出小写的单词 string t16 = "This is A Test of lowercase"; &nbsp;&nbsp; &nbsp; 　　string p16 = @"(\b[^\WA-Z0-9_]+\b)"; &nbsp;&nbsp; &nbsp; 　　MatchCollection mc16 = Regex.Matches(t16, p16);&nbsp; &nbsp;&nbsp;&nbsp; 找出第一个字母为大写的单词 string t17 = "This is A Test of Initial Caps"; &nbsp;&nbsp; &nbsp; 　　string p17 = @"(\b[^\Wa-z0-9_][^\WA-Z0-9_]*\b)"; &nbsp;&nbsp; &nbsp; 　　MatchCollection mc17 = Regex.Matches(t17, p17); &nbsp;&nbsp;&nbsp; 找出简单的HTML语言中的链接 &nbsp; string t18 = @" &nbsp;&nbsp; &nbsp; 　　&lt;html&gt; &nbsp;&nbsp; &nbsp; 　　&lt;a href=""first.htm""&gt;first tag text&lt;/a&gt; &nbsp;&nbsp; &nbsp; 　　&lt;a href=""next.htm""&gt;next tag text&lt;/a&gt; &nbsp;&nbsp; &nbsp; 　　&lt;/html&gt; &nbsp;&nbsp; &nbsp; 　　"; &nbsp;&nbsp; &nbsp; 　　string p18 = @"&lt;A[^&gt;]*?HREF\s*=\s*[""']?" + @"([^'"" &gt;]+?)[ '""]?&gt;"; &nbsp;&nbsp; &nbsp; 　　MatchCollection mc18 = Regex.Matches(t18, p18, "si"); </td> 
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