Excel ISTEXT alternative? - excel

Question

I am currently building a numberplate checker on an excel spread sheet that will determine if the letters and numbers of the numberplate are in the correct places and are valid.
The 3 criteria I have are if the numberplates are in on of these formulas:
(I have represented a number as 1 and a letter as A)
AAA111A
A111AAA
AA11AAA
The ultimate objective is for the program to ask the question "Look at these number plates, do they follow a format as shown above."
So far I have only been able to check to see if I have numbers in certain places, however I cannot specify the characters A - Z when trying to do a search function from the left, right and centre.
=ISNUMBER(--MID(A3,1,3))
If I wanted to search within a cell for example, the first character, is it a letter a-z, return true or false? How would I go about doing this?
An example in this instance might be:
DJO148R
The formula
=ISNUMBER(--MID(A5,4,3))
This would turn back as true because the 4th character is a number and so are the next 2.
With the same numberplate, how do I change it to search for letters rather than numbers within the numberplate?

Answer 1

Here is a simpler RegEx implementation. Make sure you include references to Microsoft VBScript Regular Expressions 5.5. This will go in a new inserted module
Function PlateCheck(cell As Range) As Boolean
Dim rex As New RegExp
rex.Pattern = "[A-Z][0-9|A-Z][0-9|A-Z][0-9|A-Z][0-9|A-Z][0-9|A-Z][A-Z]"
If rex.Test(cell.Value) Then
PlateCheck = True
Else
PlateCheck = False
End If
End Function

Answer 2

As per the guys comments, here's how you do it with regex:
Make sure to include MS VB regular expressions 5.5 as a reference.
To do that, in your VBA IDE, go Tools, Reference and then look the regex reference.
Then Add this in a new module:
Function VerifyLicensePlate(ip As Range) As String
Dim regex As New RegExp
Dim inputstr As String: inputstr = ip.Value
With regex
.Global = True
.IgnoreCase = True
End With
Dim strpattern(2) As String
strpattern(0) = "[A-Z][A-Z][A-Z][0-9][0-9][0-9][A-Z]"
strpattern(1) = "[A-Z][A-Z][0-9][0-9][A-Z][A-Z][A-Z]"
strpattern(2) = "[A-Z][0-9][0-9][0-9][A-Z][A-Z][A-Z]"
For i = 0 To 2
regex.pattern = strpattern(i)
If regex.Test(inputstr) Then
VerifyLicensePlate = "Match"
Exit Function
Else
VerifyLicensePlate = "No match"
End If
Next
End Function
Output:

Answer 3

Occam's Razor would suggest,
=NOT(ISNUMBER(--MID(A5,4,3)))
... or,
=ISERROR(--MID(A5,4,3))

Answer 4

Here's a version that uses late-binding, so no need to set a reference. IT is case insensitive, as that seemed to be implied in your question, but that is easily changed.
Option Explicit
Function MatchPattern(S As String) As Boolean
Dim RE As Object
Set RE = CreateObject("vbscript.regexp")
With RE
.Global = True
.Pattern = "\b(?:[A-Z]{3}\d{3}[A-Z]|[A-Z]{2}\d{2}[A-Z]{3}|[A-Z]\d{3}[A-Z]{3})\b"
.ignorecase = True
MatchPattern = .test(S)
End With
End Function
But, as pointed out by G Serg, you don't really need regex for this:
Option Explicit
Option Compare Text 'Case Insensitive
Function MatchPattern(S As String) As Boolean
Const S1 As String = "[A-Z][A-Z][A-Z]###[A-Z]"
Const S2 As String = "[A-Z]###[A-Z][A-Z][A-Z]"
Const S3 As String = "[A-Z][A-Z]##[A-Z][A-Z][A-Z]"
MatchPattern = False
If Len(S) = 7 Then
If S Like S1 Or _
S Like S2 Or _
S Like S3 Then _
MatchPattern = True
End If
End Function
Here is a rather complicated formula that seems to match your specifications:
=AND(LEN(A1)=7,
OR(MMULT(--(CODE(MID(A1,{1,2,3,4,5,6,7},1))>64),--(TRANSPOSE(CODE(MID(A1,{1,2,3,4,5,6,7},1))<91)))={4,5}),
CODE(LEFT(A1,1))>64,CODE(LEFT(A1,1))<91,
CODE(RIGHT(A1,1))>64,CODE(RIGHT(A1,1))<91,
ISNUMBER(-MID(A1,MIN(FIND({1,2,3,4,5,6,7,8,9,0},A1&"0123456789")),
7-MMULT(--(CODE(MID(A1,{1,2,3,4,5,6,7},1))>64),--(TRANSPOSE(CODE(MID(A1,{1,2,3,4,5,6,7},1))<91))))))
Ensure we have only seven characters
The OR(MMULT... function counts the number of letters and returns TRUE if four or five.
Check to make sure first and last character is a letter
There should remain a consecutive string of either two or three digits (seven less the number of letters)
If you want to make the formula case insensitive, replace the instances of A1 with UPPER(A1)
I think the UDF solution is better.