#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "([^_\n]*)_([^_\n]*)(_.*)?"
Local $sString = "foo_bar_something-like_this-me" & @CRLF & _
"bar--foo_something-like_this-me" & @CRLF & _
"something-like--bar--foo_this-me" & @CRLF & _
"this-me--something-like--bar--foo" & @CRLF & _
""
Local $sSubst = "$2--$1$3"
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