#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)^(((apple|mango|banana)\s*)+) is (\d+)kg$"
Local $sString = "apple is 2kg" & @CRLF & _
"apple banana mango is 2kg" & @CRLF & _
"apple apple apple is 6kg" & @CRLF & _
"banana banana banana is 6kg"
Local $sSubst = "$1,$4"
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