RegEx in VBA: Break a complex string into multiple tokens?

Question

EDIT: Two additional token types added.

Hi,

I am trying to parse a line in a mmCIF Protein file into separate tokens using Excel 2000/2003. Worst case it COULD look something like this:

token1 token2 "token's 1a',1b'" 'token4"5"' 12 23.2 ? . 'token' tok'en to"ken

Which should become the following tokens:
token1
token2
token's 1a',1b' (note: the double quotes have disappeared)
token4"5" (note: the single quotes have disappeared)
12
23.2
?
.
token (note: the single quotes have disappeared)
to'ken
to"ken

I am looking to see if a RegEx is even possible to split this kind of line into tokens?

Thanks!

Paul

Answer 1

It is possible to do:

You'll need to reference "Microsoft VBScript Regular Expressions 5.5" in your VBA Project, then...

Private Sub REFinder(PatternString As String, StringToTest As String)
    Set RE = New RegExp

    With RE
        .Global = True
        .MultiLine = False
        .IgnoreCase = False
        .Pattern = PatternString
    End With

    Set Matches = RE.Execute(StringToTest)

    For Each Match In Matches
        Debug.Print Match.Value & " ~~~ " & Match.FirstIndex & " - " & Match.Length & " = " & Mid(StringToTest, Match.FirstIndex + 1, Match.Length)

        ''#You get a submatch for each of the other possible conditions (if using ORs)
        For Each Item In Match.SubMatches
            Debug.Print "Submatch:" & Item
        Next Item
        Debug.Print
    Next Match

    Set RE = Nothing
    Set Matches = Nothing
    Set Match = Nothing
    Set SubMatch = Nothing
End Sub

Sub DoIt()
    ''#This simply splits by space...
    REFinder "([.^\w]+\s)|(.+$)", "Token1 Token2 65.56"
End Sub

This is obviously just a really simple example as I'm not very knowledgable of RegExp, it's more just to show you HOW it can be done in VBA (you'd probably also want to do something more useful than Debug.Print with the resulting tokens!). I'll have to leave writing the RegExp expression to somebody else I'm afraid!

Simon

Answer 2

Nice puzzle. Thanks.

This pattern (aPatt below) gets the tokens separated, but I can't figure how to remove the outer quotes.

tallpaul() produces:

 token1
 token2
 "token's 1a',1b'"
 'token4"5"'
 12
 23.2
 ?
 .
 'token'
 tok'en
 to"ken

If you can figure out how to lose the outer quotes, please let us know. This needs a reference to "Microsoft VBScript Regular Expressions" to work.

Option Explicit
''returns a list of matches
Function RegExpTest(patrn, strng)
   Dim regEx   ' Create variable.
   Set regEx = New RegExp   ' Create a regular expression.
   regEx.Pattern = patrn   ' Set pattern.
   regEx.IgnoreCase = True   ' Set case insensitivity.
   regEx.Global = True   ' Set global applicability.
   Set RegExpTest = regEx.Execute(strng)   ' Execute search.
End Function

Function tallpaul() As Boolean
    Dim aString As String
    Dim aPatt As String
    Dim aMatch, aMatches

    '' need to pad the string with leading and trailing spaces.
    aString = " token1 token2 ""token's 1a',1b'"" 'token4""5""' 12 23.2 ? . 'token' tok'en to""ken "
    aPatt = "(\s'[^']+'(?=\s))|(\s""[^""]+""(?=\s))|(\s[\w\?\.]+(?=\s))|(\s\S+(?=\s))"
    Set aMatches = RegExpTest(aPatt, aString)

    For Each aMatch In aMatches
          Debug.Print aMatch.Value
    Next
    tallpaul = True
End Function