Re: Find instance in a string

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From: Jay B. Harlow [MVP - Outlook] (Jay_Harlow_MVP_at_msn.com)
Date: 05/27/04 

Date: Wed, 26 May 2004 19:00:49 -0500

Chris,
I would use a RegEx as the others stated, something like:

    Private Shared Function FindNumber(ByVal input As String) As String
        Static exp As New Regex("\d{4}", RegexOptions.Compiled)
        Dim match As Match = exp.Match(input)
        Return match.Groups(0).Value
    End Function

    Public Shared Sub Main()
        Debug.WriteLine(FindNumber("0104 PBR"), "0104 PBR")
        Debug.WriteLine(FindNumber("PBR XT 0105 TD"), "PBR XT 0105 TD")
        Debug.WriteLine(FindNumber("PBR XT 105 TD"), "PBR XT 105 TD")
    End Sub

If there is no 4 character number in the input, an empty string is returned
otherwise the string itself is returned. If there are more then a single
instance of 4 numbers only the first is returned.

If you need multiple matches you can use Match.Success & Match.NextMatch in
a loop, or I believe John's code.

        Dim match As Match = exp.Match(input)
        Do While match .Success
            Debug.WriteLine(match.Groups(0).Value, input)
            match = match.NextMatch()
        Loop

The following sites provide a wealth of information on regular expressions.

A tutorial & reference on using regular expressions:
http://www.regular-expressions.info/

The MSDN's documentation on regular expressions:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpgenref/html/cpconRegularExpressionsLanguageElements.asp

Hope this helps
Jay

"Chris Thunell" <cthunell@pierceassociates.com> wrote in message
news:O1rikEzQEHA.1624@TK2MSFTNGP09.phx.gbl...
> I'm looking to find in a long string an instance of 4 numbers in a row,
and
> pull out those numbers.
> For instance:
> string = "0104 PBR", i'd like to get the 0104.
> string="PBR XT 0105 TD", i'd like to get the 0105.
> The numbers will always be 4 digits together.
> (I'm using vb.net)
> Any help would be greatly appreciated!
> Chris
> cthunell@pierceassociates.com
>
>

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