Question

假设我有一根绳子，“猫猫猫狗狗狗。”

我将使用什么正则表达式来替换“猫与狗”的字符串。即删除重复项。但是，表达式只能删除彼此之后的重复项。例如：

“猫猫猫狗狗狗猫猫猫狗”

会回来：

“猫与狗，猫与狗”

Answer 1

resultString = Regex.Replace(subjectString, @"\b(\w+)(?:\s+\1\b)+", "$1");

将在一次通话中完成所有替换。

说明：

\b                 # assert that we are at a word boundary
                   # (we only want to match whole words)
(\w+)              # match one word, capture into backreference #1
(?:                # start of non-capturing, repeating group
   \s+             # match at least one space
   \1              # match the same word as previously captured
   \b              # as long as we match it completely
)+                 # do this at least once

Answer 2

将(\w+)\s+\1替换为$1

在循环中执行此操作，直到找不到更多匹配项。设置global标志是不够的，因为它不会替换cats中的第三个cats cats cats

正则表达式中的

\1指的是第一个捕获组的内容。

尝试：

str = "cats cats cats and dogs dogs dogs and cats cats and dogs dogs";
str = Regex.Replace(str, @"(\b\w+\b)\s+(\1(\s+|$))+", "$1 ");
Console.WriteLine(str);

Answer 3

毫无疑问，有一个较小的正则表达式可能，但这个似乎可以解决问题：

string somestring = "cats cats cats and dogs dogs dogs and cats cats and dogs dogs";
Regex regex = new Regex(@"(\w+)\s(?:\1\s)*(?:\1(\s|$))");
string result = regex.Replace(somestring, "$1$2");

它还考虑到最后一只没有以空格结尾的“狗”。

Answer 4

请尝试以下代码。

<小时/>


using System;
using System.Text.RegularExpressions;

namespace ConsoleApplication1
{
   /// <summary>
   ///

   ///  A description of the regular expression:
   ///

   ///  Match expression but don't capture it. [^|\s+]
   ///      Select from 2 alternatives
   ///          Beginning of line or string
   ///          Whitespace, one or more repetitions
   ///  [1]: A numbered capture group. [(\w+)(?:\s+|$)]
   ///      (\w+)(?:\s+|$)
   ///          [2]: A numbered capture group. [\w+]
   ///              Alphanumeric, one or more repetitions
   ///          Match expression but don't capture it. [\s+|$]
   ///              Select from 2 alternatives
   ///                  Whitespace, one or more repetitions
   ///                  End of line or string
   ///  [3]: A numbered capture group. [\1|\2], one or more repetitions
   ///      Select from 2 alternatives
   ///          Backreference to capture number: 1
   ///          Backreference to capture number: 2
   ///

   ///
   /// </summary>
   class Class1
    {
        /// 
        /// Point d'entrée principal de l'application.
        /// 
        static void Main(string[] args)
        {
            Regex regex = new Regex(
                "(?:^|\s+)((\w+)(?:\s+|$))(\1|\2)+",
                RegexOptions.IgnoreCase
                | RegexOptions.Compiled
                );
            string str = "cats cats cats and dogs dogs dogs and cats cats and dogs dogs";
            string regexReplace = " $1";

        Console.WriteLine("Before :" + str);

        str = regex.Replace(str,regexReplace);

        Console.WriteLine("After :" + str);
    }
}

}

如何摆脱正则表达式中的重复

4 个答案: