Date cleanup function - vba

Question

I have this VBA module in my Excel spreadsheet that attempts to clean up the date data, which contains various issues with text being combined with date information. Here is my main load function:
Public lstrow As Long, strDate As Variant, stredate As Variant
Sub importbuild()
lstrow = Worksheets("Data").Range("G" & Rows.Count).End(xlUp).Row
Function DateOnlyLoad(col As String, col2 As String, colcode As String)
Dim i As Long, j As Long, k As Long
j = Worksheets("CI").Range("A" & Rows.Count).End(xlUp).Row + 1
k = Worksheets("Error").Range("A" & Rows.Count).End(xlUp).Row + 1
For i = 2 To lstrow
strDate = spacedate(Worksheets("Data").Range(col & i).Value)
stredate = spacedate(Worksheets("Data").Range(col2 & i).Value)
If (Len(strDate) = 0 And (col2 = "NA" Or Len(stredate) = 0)) Or InStr(1,
UCase(Worksheets("Data").Range(col & i).Value), "EXP") > 0 Then
GoTo EmptyRange
Else
Worksheets("CI").Range("A" & j & ":C" & j).Value =
Worksheets("Data").Range("F" & i & ":H" & i).Value
Worksheets("CI").Range("D" & j).Value = colcode
Worksheets("CI").Range("E" & j).Value = datecleanup(strDate)
'Worksheets("CI").Range("L" & j).Value = dateclean(strDate)
Worksheets("CI").Range("F" & j).Value = strDate
If col2 <> "NA" Then
If IsEmpty(stredate) = False Then
Worksheets("CI").Range("F" & j).Value = datecleanup(stredate)
End If
End If
j = j + 1
End If
EmptyRange:
Next i
End Function
datecleanup function:
Function datecleanup(inputdate As Variant) As Variant
If Len(inputdate) = 0 Then
inputdate = "01/01/1901"
Else
If Len(inputdate) = 4 Then
inputdate = "01/01/" & inputdate
Else
If InStr(1, inputdate, ".") Then
inputdate = Replace(inputdate, ".", "/")
End If
End If
End If
datecleanup = Split(inputdate, Chr(32))(0)
Sample Output:
Column A Column B Column C Column D Column E Column F
125156 Wills, C 11/8/1960 MMR1 MUMPS MUMPS TITER 02/26/2008 POSITIVE
291264 Balti, L 09/10/1981 MMR1 (blank) Measles - 11/10/71 Rubella
943729 Barnes, B 10/10/1965 MMR1 MUMPS MUMPS TITER 10/08/2008 POSITIVE
The Split separates the date from the subsequent text and this works fine, however if there is text that occurs before the date then the output contains the first part of the text. I would like to get only the date (if it exists) from the string and display that, regardless of where it falls in the string. Below are sample results: Column E is the output from the Split logic, Column F is the entire string that is being evaluated from the other worksheet.
Desired Output from above examples: (Column E has correct dates extracted)
Column A Column B Column C Column D Column E Column F
125156 Wills, C 11/8/1960 MMR1 02/26/2008 MUMPS TITER 02/26/2008 POSITIVE
291264 Balti, L 09/10/1981 MMR1 11/10/71 Measles - 11/10/71 Rubella
943729 Barnes, B 10/10/1965 MMR1 10/08/2008 MUMPS TITER 10/08/2008 POSITIVE
What else can I add into my datecleanup function to further refine this? Thanks in advance!

Answer 1

Avoiding a regex, such as in the way suggested in comments is usually a good idea, but in for a penny, in for a pound:
① Use a regex mm/dd/yyyy
(0[1-9]|1[012])[- \/.](0[1-9]|[12][0-9]|3[01])[- \/.](19|20)[0-9]{2}
That pattern comes from ipr101's answer, and proposes a good regex for validating an actual date for mm/dd/yyyy. I have adjusted to correctly escape a couple of characters.
You would need to adjust if can be less digits or different format. Some examples given below.
You could use the function below as:
Worksheets("CI").Range("F" & j).Value = RemoveChars(datecleanup(stredate))
Example test:
Option Explicit
Public Sub test()
Debug.Print RemoveChars("Measles - 11/10/1971 Rubella")
End Sub
Public Function RemoveChars(ByVal inputString As String) As String
Dim regex As Object, tempString As String
Set regex = CreateObject("VBScript.RegExp")
With regex
.Global = True
.MultiLine = True
.IgnoreCase = False
.Pattern = "(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)[0-9]{2}"
End With
If regex.test(inputString) Then
RemoveChars = regex.Execute(inputString)(0)
Else
RemoveChars = inputString
End If
End Function
② For dd/mm/yyyy use:
(0[1-9]|[12][0-9]|3[01])[- \/.](0[1-9]|1[012])[- \/.](19|20)[0-9]{2}
③ And more flexible in case of single day or month (day before month), use:
([1-9]|[12][0-9]|3[01])[- \/.](0?[1-9]|1[012])[- \/.][0-9]{2,4}
You get the idea.
Note:
You can always use something generic like (\d{1,2}\/){2}\d{2,4}, and then validate the function return string with ISDATE(return value).