[RESOLVED] How to display duplicate string in text box?

Dear all expert programmers,
Please tell me how to hightlight duplicate string in text box. Please see example below

Sample1 :
Cat Bat Mat Eat Cow Start Begin Cat
Duplicate string is Cat


Sample2 :
Cat Bat Cow Mat Eat Cow Start Begin Cat
Duplicate string is Cat, Cow

Thank you for all answers.

Use Split function to split the string into an array, then loop through it to find duplicates.

Here's a HORRIBLE way to do it:

Code:

---

Private Function ListDupes(str As String) As String
    Dim sS() As String, x As Long, dupe As String, wow As String
    sS = Split(str & " ")
    For x = 0 To UBound(sS) - 1
        If InStrB(1, dupe, ", " & sS(x)) > 0 Then
            wow = wow & ", " & sS(x)
        End If
        dupe = dupe & ", " & sS(x)
    Next x
    If LenB(wow) > 0 Then
        wow = Mid$(wow, 3)
    End If
    ListDupes = wow
End function

---

Adding a bit to what baja_yu suggested: Split, sort and loop through. Sorting makes it easier to find the duplicates, because the same ones are in a group, so you don't need to loop through all other items for each item to find the duplicates.

Here is something that isn't often suggested: Filter.

Code:

---

Option Explicit

Private Sub Form_Load()
    Dim strArray() As String, lngUB As Long, strRemove As String
    strArray = Split("Cat Bat Cow Mat Eat Cow Start Begin Cat")
    Do While UBound(strArray) > 0
        lngUB = UBound(strArray)
        strRemove = strArray(0)
        strArray = Filter(strArray, strRemove, False)
        If UBound(strArray) + 1 < lngUB Then Debug.Print strRemove
    Loop
End Sub

---