#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(\d)(-\d*\.)"
Local $sString = "1 0.00000E+00-7.52896E-04 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 1.00247E-01 0.00000E+00" & @CRLF & _
"9 2.57945E+00-9.98377E-04 0.00000E+00 1.80923E+02 0.00000E+00 0.00000E+00 1.08995E+03 0.00000E+00 0.00000E+00 1.00795E+01 1.00002E-01 0.00000E+00" & @CRLF & _
"18 2.37285E+00-2.20000E-01 0.00000E+00 1.81079E+02-5.53001E+00 0.00000E+00 1.30827E+03 2.01207E+03 0.00000E+00 9.87285E+00 8.64615E-01 0.00000E+00"
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