Using Regular expression in VBA - regex

Question

This is my sample record in a Text format with comma delimited
901,BLL,,,BQ,ARCTICA,,,,
i need to replace ,,, to ,,
The Regular expression that i tried
With regex
.MultiLine = False
.Global = True
.IgnoreCase = False
.Pattern="^(?=[A-Z]{3})\\,{3,}",",,"))$ -- error
Now i want to pass Line from file to Regex to correct the record, can some body guide me to fix this i am very new to VBA
I want to read the file line by line pass it to Regex

Answer 1

Looking at your original pattern I tried using .Pattern = "^\d{3},\D{3},,," which works on the sample record as with the 3 number characters , 3 letters,,,
In the answer I have used a more generalised pattern .Pattern = "^\w*,\w*,\w*,," This also works on the sample and mathces 3 commas each preceded with 0 or more alphanumeric characters followed directly by a fourth comma. Both patterns require a match to be from the begining of the string.
Pattern .Pattern = "^\d+,[a-zA-Z]+,\w*,," also works on the sample record. It would specify that before the first comma there should be 1 or greater numeric characters (and only numeric characters) and before the second comma ther should be 1 or more letters (and only letters). Before the 3rd comma there could be 0 or more alphanumeric characters.
The left function removes the rightmost character in the match ie. the last comma to generate the string used by the Regex.Replace.
Sub Test()
Dim str As String
str = "901,BLL,,,BQ,ARCTICA,,,,"
Debug.Print
Debug.Print str
str = strConv(str)
Debug.Print str
End Sub
Function strConv(ByVal str As String) As String
Dim objRegEx As Object
Dim oMatches As Object
Dim oMatch As Object
Set objRegEx = CreateObject("VBScript.RegExp")
With objRegEx
.MultiLine = False
.IgnoreCase = False
.Global = True
.Pattern = "^\w*,\w*,\w*,,"
End With
Set oMatches = objRegEx.Execute(str)
If oMatches.Count > 0 Then
For Each oMatch In oMatches
str = objRegEx.Replace(str, Left(oMatch.Value, oMatch.Length - 1))
Next oMatch
End If
strConv = str
End Function

Answer 2

Try this
Sub test()
Dim str As String
str = "901,BLL,,,BQ,ARCTICA,,,,"
str = strConv(str)
MsgBox str
End Sub
Function strConv(ByVal str As String) As String
Dim objRegEx As Object, allMatches As Object
Set objRegEx = CreateObject("VBScript.RegExp")
With objRegEx
.MultiLine = False
.IgnoreCase = False
.Global = True
.Pattern = ",,,"
End With
strConv = objRegEx.Replace(str, ",,")
End Function