Regular expressions

I'm working with l-systems and would like to know if it is possible to access regular expressions in vb.net components, like in the following example:

Dim StringToCheck As String = "EEOOAA"
Dim StringToFind As String = "A"
Dim exp As New Regex(StringToFind, RegexOptions.IgnoreCase)
Dim Occurrences As Integer = exp.Matches(StringToCheck).Count

This returns an error that Regex is not defined, but i cannot import, else i suppose i would just include the following:

Imports System.Text.RegularExpressions

I know my problem can be solved in other ways, but in the long run regular expressions could come in handy. Is there any way to access them?

/Thomas

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Permalink Reply by Giulio Piacentino on September 24, 2009 at 6:11am

Hi Thomas, a good way is to use the standard namespaced class definition:

Dim StringToCheck As String = "EEOOAA"

Dim StringToFind As String = "A"

Dim exp As New System.Text.RegularExpressions.Regex (StringToFind, System.Text.RegularExpressions.RegexOptions.IgnoreCase)

Dim Occurrences As Integer = exp.Matches(StringToCheck).Count

A = Occurrences

Now you can harness regular expressions fully. Btw, to take advantage of the Regex cache, use the static methods of the Regex class: e.g. System.Text.RegularExpressions.Regex.Replace() (see static signatures here) and read a discussion here: "The 2.0 Regex class no longer caches parsed regular expressions created by Regex instance methods, it only caches regular expressions created by Regex static methods".

Hope this helps,
Giulio