Regex match a specific string

Question

I am trying to extract the string <Num> from within Barcode(_<Num>_).PDF using Regex. I am looking at Regular Expression Language - Quick Reference but it is not easy. Thanks for any help.

    Dim pattern As String = "^Barcode(_+_)\.pdf" 
    If Regex.IsMatch("Barcode(_abc123_).pdf", pattern) Then
        Debug.Print("match")
    End If

You need a \d before the + otherwise you are just matching underscores — John La Rooy
– John La Rooy, Commented Mar 12, 2014 at 1:06
What's an example file name look like? Barcode_123_.pdf? Or something else? — Ahmad Mageed
– Ahmad Mageed, Commented Mar 12, 2014 at 1:10
like Barcode(_abc123_).pdf; could be numbers or string; I want the abc123 — D_Bester
– D_Bester, Commented Mar 12, 2014 at 1:12

cwa76 · Accepted Answer · 2014-03-12 01:22:21Z

1

If you are trying to not only match but also READ the value of into a variable, then you will need to call the Regex.Match method instead of simply calling the boolean isMatch method. The Match method will return a Match object that will let you get to the groups and captures from your pattern.

Your pattern would need be something like "Barcode\(_(.*)_\)\.pdf"-- note the inner parenthesis which will create a capture group for you to obtain the value of the string between the underscores.. See a MSDN docs for examples of almost exactly what you are doing.

edited Mar 12, 2014 at 1:22

answered Mar 12, 2014 at 1:11

cwa76

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2 Comments

D_Bester Over a year ago

I tried that but it didn't match yet; I will check out the website you mentioned

cwa76 Over a year ago

Actually it varies by language... I will edit my answer, I think using Vb.net you will want to escape the real parentheses, not the grouping ones. ie "Barcode(_(.*)_)\.pdf"

Kill Console · Accepted Answer · 2014-03-12 01:45:55Z

1

I don't know the regex in VB, but I can offer you a website to examine the correctness of your regex: Regex Tester. In this case, if the <Num> is numbers, you can use "Barcode(_\d+_).pdf"

edited Mar 12, 2014 at 1:45

answered Mar 12, 2014 at 1:11

Kill Console

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2 Comments

D_Bester Over a year ago

I tried your pattern with "Barcode(_123_).pdf" but it didn't match; I'll check out the Regex Tester

D_Bester Over a year ago

Thanks for the link to the tester; That's great!

D_Bester · Accepted Answer · 2014-03-12 02:12:06Z

0

Just for the record, this is what I ended up using:

    'set up regex
    'I'm using + instead of * in the pattern to ensure that if no value is
    'present the match will fail
    Dim pattern As String = "Barcode\(_(.+)_\)\.pdf"
    Dim r As Regex = New Regex(pattern, RegexOptions.IgnoreCase)

    'get match
    Dim mat As Match
    mat = r.Match("Barcode(_abc123_).pdf")

    'output the matched string
    If mat.Success Then
        Dim g As Group = mat.Groups(1)
        Dim cc As CaptureCollection = g.Captures
        Dim c As Capture = cc(0)
        Debug.Print(c.ToString)
    End If

.NET Framework Regular Expressions

edited Mar 12, 2014 at 2:12

answered Mar 12, 2014 at 1:45

D_Bester

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