Regex pattern to remove certain prefixes in a word from Excel - excel

Question

I am trying to cleanup a set of strings in Excel to extract certain words after removing some prefixes and extra characters. Initially I was trying this with FIND, LEFT, MID, etc. Then, I came across this helpful post and trying my hand at regex.
https://superuser.com/questions/794536/excel-formulas-for-stripping-out-prefix-suffix-around-number
I have used the UDF given there called Remove which takes a regex argument. Now, I am still not able to remove all the items I wanted to remove.
In the attached Excel you can see what I have tried and what the answer I am looking.
Here are the Prefixes I wanted to remove:
The numbers in the beginning surrounded by brackets - Ideally I want this in a separate column.
Anyword before a hyphen here there are a number of them 'l-', 'al-'
and then these prefixes below.
 bi
 bil
 fa
 wa
 wal
How do I write a single regex which would remove all the above prefixes?
Here is the UDF I am using:
Function Remove(objCell As Range, strPattern As String)
Dim RegEx As Object
Set RegEx = CreateObject("VBScript.RegExp")
RegEx.Global = True
RegEx.Pattern = strPattern
Remove = RegEx.Replace(objCell.Value, "")
End Function
Here is the link to the XLSM file which contains the data I have:
https://www.dropbox.com/s/et9ee727ompj5fl/Regex%20Trials.xlsm?dl=0
and here is a screenshot to show you what I am looking for:

Answer 1

Not 100% perfect for words but should get you started
Breakdown of RegEx (\d+\:)+\d+
(\d+\:) finds any patterns that match the format x:
the plus after the bracket then tells it that this is a repeating pattern.
lastly the \d+ matches the last digit in the string so that the regex will find a pattern that matches x:x:x
The next RegEx (?!l-|al-|a-|wa-|fa-|bi-)[a-z].* is a lot more complex.
First of all lets look at the [a-z]. This tells it to match any character between a and z. We then want to capture the rest of the word so by using .* it captures everything from the first match to the end of the string (this includes non a-z characters). However, we don't want it to capture the first part of the string before the hyphen (in most cases) so by using ?! We use what's called negative look ahead. This looks for anything inside the brackets and ignores those bits. | simply means or. so anything inside that bracket will be ignored from the match.
Go to http://regexr.com/ if you want to have a play around is a handy site to learn/test RegEx
Public Sub test()
Dim rng As Range
Dim matches
Dim c
With Sheet1
Set rng = .Range(.Cells(2, 1), .Cells(.Cells(.Rows.Count, 1).End(xlUp).Row, 1))
End With
For Each c In rng
With c
.Offset(0, 6) = ExecuteRegEx(.Value2, "(\d+\:)+\d+")
.Offset(0, 7) = ExecuteRegEx(.Value2, "(?!l-|al-|a-|wa-|fa-|bi-)[a-z].*")
End With
Next c
End Sub
Public Function ExecuteRegEx(str As String, pattern As String) As String
Dim RegEx As Object
Dim matches
Set RegEx = CreateObject("VBScript.RegExp")
With RegEx
.Global = True
.ignorecase = False
.pattern = pattern
If .test(str) Then
Set matches = .Execute(str)
ExecuteRegEx = matches(0)
Else
ExecuteRegEx = vbNullString
End If
End With
End Function

Answer 2

I wouldn't use a regex for this: you can do some splitting of the cell value and testing of the prefixs against a defined array of prefixs:
Note: the array values are in an order where substrings of other prefixs are later in the list
Public Function RemovePrefix(RngSrc As Range) As String
If RngSrc.Count > 1 Then Exit Function
On Error GoTo ExitFunction
Dim Prefixs() As String: Prefixs = Split("wal,wa',wa,bil,bi,fa", ",")
Dim Arr() As String, i As Long, Temp As String
Arr = Split(RngSrc, "-")
If UBound(Arr) > 0 Then
RemovePrefix = Arr(UBound(Arr))
Exit Function
End If
Arr = Split(RngSrc, " ")
For i = 0 To UBound(Prefixs)
Temp = Arr(UBound(Arr))
If InStr(Temp, Prefixs(i)) = 1 Then
RemovePrefix = Right(Temp, Len(Temp) - Len(Prefixs(i)))
Exit Function
End If
Next i
RemovePrefix = Temp
ExitFunction:
If Err Then RemovePrefix = "Error"
End Function