How to include variable in Regular expression pattern

Question

I am working on a vba macro which uses regular expression to search for a string pattern in another string.

Regex pattern includes a string (APR24 in code below) which varies. I need to know how to include a variable in the pattern.Could any one please help.

My code is as below

Public Function Regexsrch(ByVal str2bsrchd As String, ByVal str2srch As String) As Boolean
Dim Regex As New VBScript_RegExp_55.RegExp
Dim matches, s
Regex.Pattern = "(\.|\s)APR24(,|\s|\()"
Regex.IgnoreCase = True
    If Regex.Test(str2bsrchd) Then
         Regexsrch = True
Else
        Regexsrch = False
End If
End Function

Erik Nedwidek · Accepted Answer · 2013-01-24 23:13:49Z

5

So str2srch is "APR24" or some variation? If that is the case you just use concatenation to build up your pattern string.

Public Function Regexsrch(ByVal str2bsrchd As String, ByVal str2srch As String) As Boolean
Dim Regex As New VBScript_RegExp_55.RegExp
Dim matches, s
Regex.Pattern = "(\.|\s)" + str2srch + "(,|\s|\()"
Regex.IgnoreCase = True
    If Regex.Test(str2bsrchd) Then
         Regexsrch = True
Else
        Regexsrch = False
End If
End Function

answered Jan 24, 2013 at 23:13

Erik Nedwidek

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1 Comment

robinCTS Over a year ago

The regex can be improved by using character classes, eg, Regex.Pattern = "[.\s]" + str2srch + "[,\s(]"

Siddharth Rout · Accepted Answer · 2013-01-24 23:25:22Z

1

You can specify whatever pattern you want in str2srch and then assign that to Regex.Pattern

For example

Sub Sample()
    Debug.Print Regexsrch("APR24ddd", "APR24")  '<~~ Returns True
    Debug.Print Regexsrch("APR277ddd", "APR24") '<~~ Returns False
End Sub

Public Function Regexsrch(ByVal str2bsrchd As String, ByVal str2srch As String) As Boolean
    Dim Regex As New VBScript_RegExp_55.RegExp
    Dim matches, s

    Regex.Pattern = str2srch
    Regex.IgnoreCase = True

    If Regex.Test(str2bsrchd) Then
         Regexsrch = True
    Else
        Regexsrch = False
    End If
End Function

FOLLOWUP

Even if it is dynamic you can always pass the pattern as

Debug.Print Regexsrch("APR24ddd", "(\.|\s)" & VARIABLE & "(,|\s|\()").

This gives you the flexibility of using whatever pattern you want to pass to the function and you are not limited to one pattern...

edited Jan 24, 2013 at 23:25

answered Jan 24, 2013 at 23:05

Siddharth Rout

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2 Comments

Siddharth Rout Over a year ago

See followup in the post above

Siddharth Rout Over a year ago

@Downvoter: I don't mind the downvote but at least have the decency to leave a comment as to why you feel a downvote is required? Or is the too much to ask for?

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