#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)(?<!\\)(?:\\{2})*(?:"[^\\"]*(?:\\.[^"\\]*)*"|'[^\\']*(?:\\.[^'\\]*)*')(*SKIP)(*F)|\h+"
Local $sString = "2 + 2" & @CRLF & _
"2+2" & @CRLF & _
"f( " ")" & @CRLF & _
"f(" ")" & @CRLF & _
"f("Test \"mystring\" .")" & @CRLF & _
"f("Test \"mystring\" .")" & @CRLF & _
"f("' ", " ")" & @CRLF & _
"f("' "," ")"
Local $sSubst = ""
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