Define a regular expression for repeated words

 

using System;
using System.Text.RegularExpressions;

public class Test
{

    public static void Main ()
    {

        Regex rx = new Regex(@"\b(?<word>\w+)\s+(\k<word>)\b",RegexOptions.Compiled | RegexOptions.IgnoreCase);
        string text = "this is is a test.";
        MatchCollection matches = rx.Matches(text);
        Console.WriteLine("{0} matches found in:\n   {1}", matches.Count, text);
        foreach (Match match in matches)
        {
            GroupCollection groups = match.Groups;
            Console.WriteLine("'{0}' repeated at positions {1} and {2}",  
                              groups["word"].Value, 
                              groups[0].Index, 
                              groups[1].Index);
        }
    }
}

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Define a regular expression for repeated words : Regular Expression « Development Class « C# / C Sharp

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