#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)(\d*\.\d*)( lb \(\d*\.*\d* kg\))"
Local $sString = "Age Weight Length" & @CRLF & _
"0 7.4 lb (3.3 kg) 19.6" (49.8 cm)" & @CRLF & _
"1 21.3 lb (9.6 kg) 29.8" (75.7 cm)" & @CRLF & _
"2 27.5 lb (12.5 kg) 34.2" (86.8 cm)" & @CRLF & _
"3 31.0 lb (14.0 kg) 37.5" (95.2 cm)" & @CRLF & _
"4 36.0 lb (16.3 kg) 40.3" (102.3 cm)" & @CRLF & _
"5 40.5 lb (18.4 kg) 43.0" (109.2 cm)" & @CRLF & _
"6 45.5 lb (20.6 kg) 45.5" (115.5 cm)" & @CRLF & _
"7 50.5 lb (22.9 kg) 48.0" (121.9 cm)" & @CRLF & _
"8 56.5 lb (25.6 kg) 50.4" (128 cm)" & @CRLF & _
"9 63.0 lb (28.6 kg) 52.5" (133.3 cm)" & @CRLF & _
"10 70.5 lb (32 kg) 54.5" (138.4 cm)" & @CRLF & _
"11 78.5 lb (35.6 kg) 56.5" (143.5 cm)" & @CRLF & _
"12 88.0 lb (39.9 kg) 58.7" (149.1 cm)" & @CRLF & _
"13 100.0 lb (45.3 kg) 61.5" (156.2 cm)" & @CRLF & _
"14 112.0 lb (50.8 kg) 64.5" (163.8 cm)" & @CRLF & _
"15 123.5 lb (56.0 kg) 67.0" (170.1 cm)" & @CRLF & _
"16 134.0 lb (60.8 kg) 68.3" (173.4 cm)" & @CRLF & _
"17 142.0 lb (64.4 kg) 69.0" (175.2 cm)" & @CRLF & _
"18 147.5 lb (66.9 kg) 69.2" (175.7 cm)" & @CRLF & _
"19 152.0 lb (68.9 kg) 69.5" (176.5 cm)" & @CRLF & _
"20 155.0 lb (70.3 kg) 69.7" (177 cm)" & @CRLF & _
""
Local $sSubst = "\1"
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