Add a space after comma using VBA regex - regex

Question

I'm trying to use a regex to find cells in a range that have a comma, but no space after that comma. Then, I want to simply add a space between the comma and the next character. For example, a cell has Wayne,Bruce text inside, but I want to turn it to Wayne, Bruce.
I have a regex pattern that can find cells with characters and commas without spaces, but when I replace this, it cuts off some characters.
Private Sub simpleRegexSearch()
' adapted from http://stackoverflow.com/questions/22542834/how-to-use-regular-expressions-regex-in-microsoft-excel-both-in-cell-and-loops
Dim strPattern As String: strPattern = "[a-zA-Z]\,[a-zA-Z]"
Dim strReplace As String: strReplace = ", "
Dim regEx As New RegExp
Dim strInput As String
Dim Myrange As Range
Set Myrange = ActiveSheet.Range("P1:P5")
For Each cell In Myrange
If strPattern <> "" Then
strInput = cell.Value
With regEx
.Global = True
.MultiLine = True
.IgnoreCase = False
.Pattern = strPattern
End With
If regEx.TEST(strInput) Then
Debug.Print (regEx.Replace(strInput, strReplace))
Else
Debug.Print ("No Regex Not matched in " & cell.address)
End If
End If
Next
Set regEx = Nothing
End Sub
If I run that against "Wayne,Bruce" I get "Wayn, ruce". How do I keep the letters, but separate them?

Answer 1

Change the code the following way:
Dim strPattern As String: strPattern = "([a-zA-Z]),(?=[a-zA-Z])"
Dim strReplace As String: strReplace = "$1, "
Output will be Bruce, Wayne.
The problem is that you cannot use a look-behind in VBScript, so we need a workaround in the form of a capturing group for the letter before the comma.
For the letter after the comma, we can use a look-ahead, it is available in this regex flavor.
So, we just capture with ([a-zA-Z]) and restore it in the replacing call with a back-reference $1. Look-ahead does not consume characters, so we are covered.
(EDIT) REGEX EXPLANATION
([a-zA-Z]) - A captured group that includes a character class matching just 1 English character
, - Matching a literal , (you actually do not have to escape it as it is not a special character)
(?=[a-zA-Z]) - A positive look-ahead that only checks (does not match, or consume) if the immediate character following the comma is and English letter.

Answer 2

If we replace all commas with comma+space and then replace comma+space+space with comma+space, we can meet your requirement:
Sub NoRegex()
Dim r As Range
Set r = Range("P1:P5")
r.Replace What:=",", Replacement:=", "
r.Replace What:=", ", Replacement:=", "
End Sub

Answer 3

Uses the same RegExp as in the solution from stribizhev but with two optimisations for speed
Your current code sets the RegExp details for every cell tested, these only need setting once.
Looping through a varinat array is much faster than a cell range
code
Private Sub simpleRegexSearch()
' adapted from http://stackoverflow.com/questions/22542834/how-to-use-regular-expressions-regex-in-microsoft-excel-both-in-cell-and-loops
Dim strPattern As String:
Dim strReplace As String:
Dim regEx As Object
Dim strInput As String
Dim X, X1
Dim lngnct
Set regEx = CreateObject("vbscript.regexp")
strPattern = "([a-zA-Z])\,(?=[a-zA-Z])"
strReplace = "$1, "
With regEx
.Global = True
.MultiLine = True
.IgnoreCase = False
.Pattern = strPattern
X = ActiveSheet.Range("P1:P5").Value2
For X1 = 1 To UBound(X)
If .TEST(X(X1, 1)) Then
Debug.Print .Replace(X(X1, 1), strReplace)
Else
Debug.Print ("No Regex Not matched in " & [p1].Offset(X1 - 1).Address(0, 0))
End If
Next
End With
Set regEx = Nothing
End Sub

Answer 4

What you are doing via Regex is to find a pattern
(any Alphabet),(any Alphabet)
and then replace such pattern to
,_
where _ implies a space.
So if you have Wayne,Bruce then the pattern matches where e,B. Therefore the result becomes Wayn, ruce.
Try
Dim strPattern As String: strPattern = "([a-zA-Z]),([a-zA-Z])"
Dim strReplace As String: strReplace = "$1, $2"
.