CODEWITHSUNDEEP
.netregexvb.net
monocular
monocular

Reputation: 323

Count number of groups in the regex pattern

I'm using this code to count how many group of a regex pattern contain.

Dim GroupCount As Integer = Regex.Match(input, pattern).Groups.Count

It returns success when the pattern matches the input:

Dim GroupCount As Integer = Regex.Match(" something ", "( )something( )").Groups.Count

But it's always returns 1 if the pattern doesn't match.

Dim GroupCount As Integer = Regex.Match("ABC", "( )something( )").Groups.Count

What I need is a function to count number of groups in a pattern in any case.

Upvotes: 3

Views: 2054

Answers (3)

devavx
devavx

Reputation: 1045

If I am getting you correctly then you need to count instances of ( ) in any word.Well If I am correct then this should help you;

Dim s As String = "( )yourstring()somevalue( )getit()"
            'A sample string.
Dim rgx As New Regex("(?<BraceGroup>\([ ]*\))", RegexOptions.Singleline)
            'Regex pattern to match '( )' or '()'.
Dim matches As MatchCollection = rgx.Matches(s)
            'Get all matches.
Dim count As Integer = matches.Count
            'Number of matches.
Console.WriteLine(String.Format("Total '() captures' found : {0}", count))

Ideone demo here.

Upvotes: 0

Martin Ender
Martin Ender

Reputation: 44259

How about Regex.GetGroupNumbers()?

Dim pattern As New Regex("( )something( )")
Dim groupCount As Integer = pattern.GetGroupNumbers().Length

By obtaining the result from a Regex object, it's independent of any particular match, which is just what you want.

You might want to subtract 1 from the result, because the entire string is also a group (at index 0), depending on what you are looking for.

Demo.

Upvotes: 2

Jongware
Jongware

Reputation: 22457

Read the manual:

Return Value Type: System.Text.RegularExpressions.Match An object that contains information about the match.

You need to test for GroupCount.Success.

Upvotes: -1

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