#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "^(?:(?:[1-9]?[0-9]|1[0-9][0-9]|2(?:[0-4][0-9]|5[0-5]))\.){3}(?:[1-9]?[0-9]|1[0-9][0-9]|2(?:[0-4][0-9]|5[0-5]))(?:\/(?:[12]?[0-9]|3[0-2]))?$"
Local $sString = "172.0.0.1/16"
Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYFULLMATCH)
; Present the entire match result
_ArrayDisplay($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