#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)(\d+ +)(AB|DE|RG|DU)"
Local $sString = "23 AB 5400 DE 68 RG" & @CRLF & _
"33 DU 88 DE 8723 AB" & @CRLF & _
"55 RG 76 AB 92 DE"
Local $sSubst = "\1\2"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
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