in the .NET Framework Class Library is the
System.Text.RegularExpressions namespace that is
devoted to creating, executing, and obtaining results from regular
expressions executed against a string.
Regular expressions take the form of a pattern that can be matched to
zero or more characters within a string. The simplest of these
patterns, such as
.* (match anything and
[A-Za-z] (match any letter) are
easy to learn, but more advanced patterns can be difficult to learn
and even more difficult to implement correctly. Learning and
understanding regular expressions can take considerable time and
effort, but the work will pay off.
Regular expression patterns can take a simple form—such as a
single word or character—or a much more complex pattern. The
more complex patterns can recognize and match such things as the year
portion of a date, all of the
in an ASP page, or a phrase in a sentence that varies with each use.
The .NET regular expression classes provide a very flexible and
powerful way to do such things as recognize text, replace text within
a string, and split up text into individual sections based on one or
more complex delimiters.
Despite the complexity of regular expression patterns, the regular expression classes in the FCL are easy to use in your applications. Executing a regular expression consists of the following steps:
instance of the
Regex object that contains the regular expression pattern ...