MatchCollection Class

Imports System.Text.RegularExpressions

Public Module Example

   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      ' Define a regular expression for repeated words.
      Dim rx As New Regex("\b(?<word>\w+)\s+(\k<word>)\b", _
                          RegexOptions.IgnoreCase)

      ' Define a test string.        
      Dim text As String = "The the quick brown fox  fox jumped over the lazy dog dog."

      ' Find matches.
      Dim matches As MatchCollection = rx.Matches(text)

      ' Report the number of matches found.
      outputBlock.Text &= String.Format("{0} matches found in:", matches.Count) & vbCrLf
      outputBlock.Text &= String.Format("   {0}", text) & vbCrLf

      ' Report on each match.
      For Each match As Match In matches
         Dim groups As GroupCollection = match.Groups
         outputBlock.Text &= String.Format("'{0}' repeated at positions {1} and {2}", _
                           groups.Item("word").Value, _
                           groups.Item(0).Index, _
                           groups.Item(1).Index) & vbCrLf
      Next
   End Sub
End Module
' The example produces the following output:
'       3 matches found in:
'          The the quick brown fox  fox jumped over the lazy dog dog.
'       'The' repeated at positions 0 and 4
'       'fox' repeated at positions 20 and 25
'       'dog' repeated at positions 50 and 54

using System;
using System.Text.RegularExpressions;

public class Example
{

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {

      // Define a regular expression for repeated words.
      Regex rx = new Regex(@"\b(?<word>\w+)\s+(\k<word>)\b",
                           RegexOptions.IgnoreCase);

      // Define a test string.        
      string text = "The the quick brown fox  fox jumped over the lazy dog dog.";

      // Find matches.
      MatchCollection matches = rx.Matches(text);

      // Report the number of matches found.
      outputBlock.Text += String.Format("{0} matches found in:\n   {1}",
                        matches.Count,
                        text) + "\n";

      // Report on each match.
      foreach (Match match in matches)
      {
         GroupCollection groups = match.Groups;
         outputBlock.Text += String.Format("'{0}' repeated at positions {1} and {2}",
                           groups["word"].Value,
                           groups[0].Index,
                           groups[1].Index) + "\n";
      }

   }

}
// The example produces the following output:
//       3 matches found in:
//          The the quick brown fox  fox jumped over the lazy dog dog.
//       'The' repeated at positions 0 and 4
//       'fox' repeated at positions 20 and 25
//       'dog' repeated at positions 50 and 54