Group Class

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Represents the results from a single capturing group.

Inheritance Hierarchy

System. . :: . .Object
  System.Text.RegularExpressions. . :: . .Capture
    System.Text.RegularExpressions..::..Group
      System.Text.RegularExpressions. . :: . .Match

Namespace:  System.Text.RegularExpressions
Assembly:  System.Text.RegularExpressions (in System.Text.RegularExpressions.dll)

Syntax

'Declaration
<SerializableAttribute> _
Public Class Group _
    Inherits Capture

[SerializableAttribute]
public class Group : Capture

[SerializableAttribute]
public ref class Group : public Capture

[<SerializableAttribute>]
type Group =  
    class
        inherit Capture
    end

public class Group extends Capture

The Group type exposes the following members.

Properties

	Name	Description
	Captures	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 RegexOptions.RightToLeft option). The collection may have zero or more items.
	Index	The position in the original string where the first character of the captured substring is found. (Inherited from Capture.)
	Length	Gets the length of the captured substring. (Inherited from Capture.)
	Success	Gets a value indicating whether the match is successful.
	Value	Gets the captured substring from the input string. (Inherited from Capture.)

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Methods

	Name	Description
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	Synchronized	Returns a Group object equivalent to the one supplied that is safe to share between multiple threads.
	ToString	Retrieves the captured substring from the input string by calling the Value property. (Inherited from Capture.)

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Remarks

A capturing group can capture zero, one, or more strings in a single match because of quantifiers. All the substrings matched by a single capturing group are available from the Group..::..Captures property. Information about the last substring captured can be accessed directly from the Value and Index properties. (That is, the Group instance is equivalent to the last item of the collection returned by the Captures property, which reflects the last capture made by the capturing group.)

An example helps to clarify this relationship between a Group object and the System.Text.RegularExpressions..::..CaptureCollection that is returned by the Captures property. The regular expression pattern (\b(\w+?)[,:;]?\s?)+[?.!] matches entire sentences. The regular expression is defined as shown in the following table.

Pattern	Description
\b	Begin the match at a word boundary.
(\w+?)	Match one or more word characters, but as few characters as possible. This is the second (inner) capturing group. (The first capturing group includes the \b language element.)
[,:;]?	Match zero or one occurrence of a comma, colon, or semicolon.
\s?	Match zero or one occurrence of a white-space character.
(\b(\w+?)[,:;]?\s?)+	Match the pattern consisting of a word boundary, one or more word characters, a punctuation symbol, and a white-space character one or more times. This is the first capturing group.
[?.!]	Match any occurrence of a period, question mark, or exclamation point.

In this regular expression pattern, the subpattern (\w+?) is designed to match multiple words within a sentence. However, the value of the Group object represents only the last match that (\w+?) captures, whereas the Captures property returns a CaptureCollection that represents all captured text. As the output shows, the CaptureCollection for the second capturing group contains four objects. The last of these corresponds to the Group object.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

See Also

Reference

System.Text.RegularExpressions Namespace