Group.Captures Group.Captures Group.Captures Group.Captures Property

Definition

Gets a collection of all the captures matched by the capturing group, in innermost-leftmost-first order (or innermost-rightmost-first order if the regular expression is modified with the RightToLeft option). The collection may have zero or more items.

public:
 property System::Text::RegularExpressions::CaptureCollection ^ Captures { System::Text::RegularExpressions::CaptureCollection ^ get(); };
public System.Text.RegularExpressions.CaptureCollection Captures { get; }
member this.Captures : System.Text.RegularExpressions.CaptureCollection
Public ReadOnly Property Captures As CaptureCollection
Property Value

The collection of substrings matched by the group.

Remarks

If a quantifier is not applied to a capturing group, the collection returned by the Captures property contains a single Capture object that provides information about the same substring as the Group object. This is illustrated in the following example. It defines a regular expression, \b(\w+)\b, that extracts a single word from a sentence. The Group object captures the word "This", and the single object in the CaptureCollection contains information about the same capture.

using System;
using System.Text.RegularExpressions;

public class Example
{
   public static void Main()
   {
      string pattern = @"\b(\w+)\b";
      string input = "This is one sentence.";
      Match match = Regex.Match(input, pattern);
      if (match.Success) {
         Console.WriteLine("Matched text: {0}", match.Value);
         for (int ctr = 1; ctr <= match.Groups.Count - 1; ctr++) {
            Console.WriteLine("   Group {0}:  {1}", ctr, match.Groups[ctr].Value);
            int captureCtr = 0;
            foreach (Capture capture in match.Groups[ctr].Captures) {
               Console.WriteLine("      Capture {0}: {1}", 
                                 captureCtr, capture.Value);
               captureCtr += 1;                  
            }
         }
      }   
   }
}
// The example displays the following output:
//       Matched text: This
//          Group 1:  This
//             Capture 0: This
Imports System.Text.RegularExpressions

Module Example
   Public Sub Main()
      Dim pattern As String = "\b(\w+)\b"
      Dim input As String = "This is one sentence."
      Dim match As Match = Regex.Match(input, pattern)
      If match.Success Then
         Console.WriteLine("Matched text: {0}", match.Value)
         For ctr As Integer = 1 To match.Groups.Count - 1
            Console.WriteLine("   Group {0}:  {1}", ctr, match.Groups(ctr).Value)
            Dim captureCtr As Integer = 0
            For Each capture As Capture In match.Groups(ctr).Captures
               Console.WriteLine("      Capture {0}: {1}", _
                                 captureCtr, capture.Value)
               captureCtr += 1                  
            Next
         Next
      End If   
   End Sub
End Module
' The example displays the following output:
'       Matched text: This
'          Group 1:  This
'             Capture 0: This

The real utility of the Captures property occurs when a quantifier is applied to a capturing group so that the group captures multiple substrings in a single regular expression. In this case, the Group object contains information about the last captured substring, whereas the Captures property contains information about all the substrings captured by the group. In the following example, the regular expression \b(\w+\s*)+\. matches an entire sentence that ends in a period. The group (\w+\s*)+ captures the individual words in the collection. Because the Group collection contains information only about the last captured substring, it captures the last word in the sentence, "sentence". However, each word captured by the group is available from the collection returned by the Captures property.

using System;
using System.Text.RegularExpressions;

public class Example
{
   public static void Main()
   {
      string input = "This is a sentence. This is another sentence.";
      string pattern = @"\b(\w+\s*)+\.";
      Match match = Regex.Match(input, pattern);
      if (match.Success) {
         Console.WriteLine("Matched text: {0}", match.Value);
         for (int ctr = 1; ctr < match.Groups.Count; ctr++) {
            Console.WriteLine("   Group {0}:  {1}", ctr, match.Groups[ctr].Value);
            int captureCtr = 0;
            foreach (Capture capture in match.Groups[ctr].Captures) {
               Console.WriteLine("      Capture {0}: {1}", 
                                 captureCtr, capture.Value);
               captureCtr++; 
            }
         }
      }   
   }
}
// The example displays the following output:
//       Matched text: This is a sentence.
//          Group 1:  sentence
//             Capture 0: This
//             Capture 1: is
//             Capture 2: a
//             Capture 3: sentence
Imports System.Text.RegularExpressions

Module Example
   Public Sub Main()
      Dim input As String = "This is a sentence. This is another sentence."
      Dim pattern As String = "\b(\w+\s*)+\."
      Dim match As Match = Regex.Match(input, pattern)
      If match.Success Then
         Console.WriteLine("Matched text: {0}", match.Value)
         For ctr As Integer = 1 To match.Groups.Count - 1
            Console.WriteLine("   Group {0}:  {1}", ctr, match.Groups(ctr).Value)
            Dim captureCtr As Integer = 0
            For Each capture As Capture In match.Groups(ctr).Captures
               Console.WriteLine("      Capture {0}: {1}", _
                                 captureCtr, capture.Value)
               captureCtr += 1                  
            Next
         Next
      End If   
   End Sub
End Module
' The example displays the following output:
'       Matched text: This is a sentence.
'          Group 1:  sentence
'             Capture 0: This
'             Capture 1: is
'             Capture 2: a
'             Capture 3: sentence

Applies to

See Also