In a specified input string, replaces all strings that match a regular expression pattern with a specified replacement string.
Syntax
Parameters
- input
- replacement
Returns
A new string that is identical to the input string, except that the replacement string takes the place of each matched string. If the regular expression pattern is not matched in the current instance, the method returns the current instance unchanged.
Remarks
The search for matches starts at the beginning of the input string. The regular expression is the pattern defined by the constructor for the current System.Text.RegularExpressions.Regex object.
The replacement parameter specifies the string that is to replace each match in input. replacement can consist of any combination of literal text and substitutions. For example, the replacement pattern a*${test}b inserts the string "a*" followed by the substring that is matched by the test capturing group, if any, followed by the string "b". The * character is not recognized as a metacharacter within a replacement pattern.
Substitutions are the only regular expression language elements that are recognized in a replacement pattern. All other regular expression language elements, including character escapes, are allowed in regular expression patterns only and are not recognized in replacement patterns.
The System.Text.RegularExpressions.RegexMatchTimeoutException exception is thrown if the execution time of the replacement operation exceeds the time-out interval specified by the Regex.#ctor(string, RegexOptions, TimeSpan) constructor. If you do not set a time-out interval when you call the constructor, the exception is thrown if the operation exceeds any time-out value established for the application domain in which the System.Text.RegularExpressions.Regex object is created. If no time-out is defined in the System.Text.RegularExpressions.Regex constructor call or in the application domain's properties, or if the time-out value is Regex.InfiniteMatchTimeout, no exception is thrown
Because the method returns input unchanged if there is no match, you can use the object.ReferenceEquals(object, object) method to determine whether the method has made any replacements to the input string.
Requirements
Assembly: System (in System.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0, 4.0.0.0