#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "(?m)\b(ATU\d{8}|BE[01]\d{9}|BG\d{9,10}|CY\d{8}[LX]|CZ\d{8,10}|DE\d{9}|DK\d{8}|EE\d{9}|EL\d{9}|ES[\dA-Z]\d{7}[\dA-Z]|FI\d{8}|FR[\dA-Z]{2}\d{9}|HR\d{11}|HU\d{8}|IE\d{7}[A-Z]{2}|IT\d{11}|LT(\d{9}|\d{12})|LU\d{8}|LV\d{11}|MT\d{8}|NL\d{9}B\d{2}|PL\d{10}|PT\d{9}|RO\d{2,10}|SE\d{12}|SI\d{8}|SK\d{10})\b"
Local $sString = "ATU12345678" & @CRLF & _
"BE1234567890" & @CRLF & _
"BG123456789" & @CRLF & _
"HR12345678901" & @CRLF & _
"CY12345678X" & @CRLF & _
"CZ12345678" & @CRLF & _
"DK12345678" & @CRLF & _
"EE123456789" & @CRLF & _
"FI12345678" & @CRLF & _
"FR12345678901" & @CRLF & _
"DE123456789" & @CRLF & _
"EL123456789" & @CRLF & _
"HU12345678" & @CRLF & _
"IE1234567WA" & @CRLF & _
"IT12345678901" & @CRLF & _
"LV12345678901" & @CRLF & _
"LT123456789" & @CRLF & _
"LU12345678" & @CRLF & _
"MT12345678" & @CRLF & _
"NL123456789B01" & @CRLF & _
"PL1234567890" & @CRLF & _
"PT123456789" & @CRLF & _
"RO1234567890" & @CRLF & _
"SK1234567890" & @CRLF & _
"SI12345678" & @CRLF & _
"ESX12345678" & @CRLF & _
"SE123456789012"
Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYGLOBALFULLMATCH)
Local $aFullArray[0]
For $i = 0 To UBound($aArray) -1
_ArrayConcatenate($aFullArray, $aArray[$i])
Next
$aArray = $aFullArray
; Present the entire match result
_ArrayDisplay($aArray, "Result")
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm