Regex.Matches Method (String, String, RegexOptions)

Updated: September 2010

Searches the specified input string for all occurrences of a specified regular expression, using the specified matching options.

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

public static MatchCollection Matches(
	string input,
	string pattern,
	RegexOptions options
)

Parameters

input
Type: System.String

The string to search for a match.

pattern
Type: System.String

The regular expression pattern to match.

options
Type: System.Text.RegularExpressions.RegexOptions

A bitwise combination of the enumeration values that specify options for matching.

Return Value

Type: System.Text.RegularExpressions.MatchCollection
A collection of the Match objects found by the search. If no matches are found, the method returns an empty collection object.

ExceptionCondition
ArgumentException

A regular expression parsing error has occurred.

ArgumentNullException

input is null.

-or-

pattern is null.

ArgumentOutOfRangeException

options is not a valid bitwise combination of RegexOptions values.

The Matches method is similar to the Match method, except that it returns information about all the matches, instead of a single match, found in the input string. It is equivalent to the following code:

The collection includes only successful matches and terminates at the first unsuccessful match.

The static Matches methods are equivalent to constructing a Regex object with the specified regular expression pattern and calling the instance method Matches.

The pattern parameter consists of various regular expression language elements that symbolically describe the string to match. For more information about regular expressions, see .NET Framework Regular Expressions and Regular Expression Language - Quick Reference.

The Matches method uses lazy evaluation to populate the returned MatchCollection object. Accessing such members of this collection as MatchCollection.Count and MatchCollection.CopyTo causes the collection to be populated immediately. To take advantage of lazy evaluation, you should iterate the collection by using a construct such as foreach in C# and For EachNext in Visual Basic.

The following example calls the Matches(String, String) method to identify any word in a sentence that ends in "es", and then calls the Matches(String, String, RegexOptions) to perform a case-insensitive comparison of the pattern with the input string. As the output shows, the two methods return different results.

using System;
using System.Text.RegularExpressions;

public class Example
{
   public static void Main()
   {
      string pattern = @"\b\w+es\b";
      string sentence = "NOTES: Any notes or comments are optional.";

      // Call Matches method without specifying any options. 
      foreach (Match match in Regex.Matches(sentence, pattern))
         Console.WriteLine("Found '{0}' at position {1}", 
                           match.Value, match.Index);
      Console.WriteLine();

      // Call Matches method for case-insensitive matching. 
      foreach (Match match in Regex.Matches(sentence, pattern, RegexOptions.IgnoreCase))
         Console.WriteLine("Found '{0}' at position {1}", 
                           match.Value, match.Index);
   }
}
// The example displays the following output: 
//       Found 'notes' at position 11 
//        
//       Found 'NOTES' at position 0 
//       Found 'notes' at position 11

The regular expression pattern \b\w+es\b 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.

es

Match the literal string "es".

\b

End the match at a word boundary.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

September 2010

Expanded the Return Value and Remarks sections.

Customer feedback.

February 2010

Added an example.

Customer feedback.

July 2009

Included additional exception information.

Content bug fix.

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