Parse substring from text

I would use InStr to find the position of the three characters that separate the values and then use Left/Right on them.

This is what I hacked together real quick:

Dim tmp, new_string, first, last, region As String

tmp = "CN=John Smith (region),OU=Legal,DC=example,DC=comand"

new_string = Right(tmp, Len(tmp) - 3)
' John Smith (region),OU=Legal,DC=example,DC=comand
new_string = Left(new_string, (InStr(1, new_string, ",") - 2))
' John Smith (region)

region = Right(new_string, Len(new_string) - InStr(1, new_string, "("))
' region
new_string = Left(new_string, (InStr(1, new_string, "(") - 2))
' John Smith

last = Right(new_string, Len(new_string) - InStr(1, new_string, " "))
' Smith
first = Left(new_string, (InStr(1, new_string, " ") - 1))
' John

Then concatenate them to get the string output you want.

This is vba.. no string.substring ;)

this is more like VB 6 (or any one below).. so you are stuck with mid, instr, len (to get the total len of a string).. I think you missed len to get the total of chars in a string? If you need some clarification just post a comment.

edit:

Another quick hack..

    Dim t As String
    t = "CN=Smith, John (region),OU=Legal,DC=example,DC=comand"
    Dim s1 As String
    Dim textstart As Integer
    Dim textend As Integer
    textstart = InStr(1, t, "CN=", vbTextCompare) + 3
    textend = InStr(1, t, "(", vbTextCompare)
    s1 = Mid(t, textstart, textend - textstart)
    MsgBox s1
    textstart = InStr(1, t, "(", vbTextCompare) + 1
    textend = InStr(1, t, ")", vbTextCompare)
    s2 = Mid(t, textstart, textend - textstart)
    MsgBox s2

Clearly your problem is that since you need a diference for the second parameter, you should always do some math for it...

I'm not sure I got your question right, but here is my implementation of (hopefully) what you want:

Function GetName(arg As String) As String
    parts = Split(arg, ",")
    For Each p In parts
        kv = Split(p, "=")
        Key = kv(0)
        Value = kv(1)
        If Key = "CN" Then
            commonName = Value
        End If
    Next p
    regIndex = InStr(1, commonName, "(")
    region = Mid(commonName, regIndex, Len(commonName) - regIndex + 1)
    parts = Split(commonName, " ")
    first = parts(0)
    last = parts(1)
    GetName = first & ", " & last & " " & region
End Function


Sub test()
 'Prints "John, Smith (region)"
 Debug.Print GetName("CN=John Smith (region),OU=Legal,DC=example,DC=comand")
End Sub

It illustrates the use of Split and Mid functions.

It is a quick and dirty implementation serving illustrative purposes only. To use it in real code you need to add several checks (e.g. that the kv and parts collections contain at least two elements).

UPD: To cover two possible formats of the CN field, namely "last\, first (region)" and "first last (region)" and make things a little less messy I would take the regular expressions approach.

Function GetName(arg As String) As String
    Dim RE As Object, REMatches As Object

    Set RE = CreateObject("vbscript.regexp")
    With RE
        .MultiLine = False
        .Global = False
        .IgnoreCase = True
        .Pattern = "CN=(\w+)\s*?(\\,)?.*?,"
    End With
    Set REMatches = RE.Execute(arg)
    If REMatches.Count < 1 Then
        GetName = ""
        Return
    End If

    cn = REMatches(0).Value
    withComma = (InStr(1, cn, "\,") > 0)
    If withComma Then
        lastIndex = 0
        firstIndex = 2
        regionIndex = 3
        patt = "(\w+)\s*?(\\,)?\s*?(\w+)\s*(\(.*?\))"
    Else
        lastIndex = 1
        firstIndex = 0
        regionIndex = 2
        patt = "(\w+)\s*?(\w+)\s*(\(.*?\))"
    End If
    Set RE = CreateObject("vbscript.regexp")
    With RE
        .MultiLine = False
        .Global = False
        .IgnoreCase = True
        .Pattern = patt
    End With
    Set REMatches = RE.Execute(arg)
    If REMatches.Count < 1 Then
        GetName = ""
        Return
    End If

    Set m = REMatches(0)
    first = m.SubMatches(firstIndex)
    last = m.SubMatches(lastIndex)
    region = m.SubMatches(regionIndex)
    GetName = first & ", " & last & " " & region
End Function


Sub test()
 ' Prints "first, last (AAA-somewhere)" two times.
 Debug.Print GetName("CN=last\, first (AAA-somewhere),OU=IT,OU=Users,OU=somewhere - aaa,OU=place,DC=aaa,DC=com")
 Debug.Print GetName("CN=first last (AAA-somewhere),OU=IT,OU=Users,OU=somewhere - aaa,OU=place,DC=aaa,DC=com")
End Sub