Regex.Matches Method (String, String, RegexOptions, TimeSpan)
Searches the specified input string for all occurrences of a specified regular expression, using the specified matching options and time-out interval.
Assemblies: System.Text.RegularExpressions (in System.Text.RegularExpressions.dll)
System (in System.dll)
static member Matches : input:string * pattern:string * options:RegexOptions * matchTimeout:TimeSpan -> MatchCollection
- Type: System.String
The string to search for a match.
- Type: System.String
The regular expression pattern to match.
- Type: System.Text.RegularExpressions.RegexOptions
A bitwise combination of the enumeration values that specify options for matching.
A regular expression parsing error occurred.
input or pattern is a null reference (Nothing in Visual Basic).
options is not a valid bitwise combination of RegexOptions values.
matchTimeout is negative, zero, or greater than approximately 24 days.
The method is similar to the Match(String, String, RegexOptions, TimeSpan) method, except that it returns information about all the matches found in the input string, instead of a single match. It is equivalent to the following code:
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 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 members of this collection such 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 Each…Next in Visual Basic.
Because of its lazy evaluation, calling the Matches method does not throw a RegexMatchTimeoutException exception. However, an exception is thrown when an operation is performed on the MatchCollection object returned by this method, if a matching operation exceeds this time-out interval specified by thematchTimeout parameter.Notes to Callers
We recommend that you set the matchTimeout parameter to an appropriate value, such as two seconds. If you disable time-outs by specifying Regex.InfiniteMatchTimeout, the regular expression engine offers slightly better performance. However, you should disable time-outs only under the following conditions:
When the input processed by a regular expression is derived from a known and trusted source or consists of static text. This excludes text that has been dynamically input by users.
When the regular expression pattern has been thoroughly tested to ensure that it efficiently handles matches, non-matches, and near matches.
When the regular expression pattern contains no language elements that are known to cause excessive backtracking when processing a near match.
The following example calls the method to perform a case-sensitive comparison that matches any word in a sentence that ends in "es". It then calls the method to perform a case-insensitive comparison of the pattern with the input string. In both cases, the time-out interval is set to one second. As the output shows, the two methods return different results.
The regular expression pattern \b\w+es\b is defined as shown in the following table.
Begin the match at a word boundary.
Match one or more word characters.
Match the literal string "es".
End the match at a word boundary.