#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "(?m)^(?=.*[A-Za-z].*[A-Za-z])([A-Za-z0-9]((?!.*[\._]{2})([\w\d\.]{1,23}))[A-Za-z0-9])$"
Local $sString = "A.s" & @CRLF & _
"0as" & @CRLF & _
"a.a" & @CRLF & _
"a.0" & @CRLF & _
"0.0" & @CRLF & _
"a._a" & @CRLF & _
"a.0a" & @CRLF & _
"1rockit.man" & @CRLF & _
"q3w" & @CRLF & _
"e4.45r.d.2" & @CRLF & _
"sp_am" & @CRLF & _
".ret." & @CRLF & _
"123" & @CRLF & _
"12a" & @CRLF & _
"ret..wer" & @CRLF & _
"super_.duper" & @CRLF & _
"_petrat or petrat_" & @CRLF & _
""
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