#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)(\{\"TimePeriod\":){1}.+?(false\}){1}"
Local $sString = "{"TimePeriod": {"Start": "2017-03-01", "End": "2017-04-01"}, "Total": {"UnblendedCost": {"Amount": "2942.25119998", "Unit": "USD"}, "UsageQuantity": {"Amount": "20835", "Unit": "Hrs"}}, "Groups": [], "Estimated": false},{"TimePeriod": {"Start": "2017-04-01", "End": "2017-05-01"}, "Total": {"UnblendedCost": {"Amount": "2982.62609983", "Unit": "USD"}, "UsageQuantity": {"Amount": "21049", "Unit": "Hrs"}}, "Groups": [], "Estimated": false},{"TimePeriod": {"Start": "2017-05-01", "End": "2017-06-01"}, "Total": {"UnblendedCost": {"Amount": "1399.04829988", "Unit": "USD"}, "UsageQuantity": {"Amount": "23010", "Unit": "Hrs"}}, "Groups": [], "Estimated": false},{"TimePeriod": {"Start": "2017-06-01", "End": "2017-07-01"}, "Total": {"UnblendedCost": {"Amount": "962.47549987", "Unit": "USD"}, "UsageQuantity": {"Amount": "20049", "Unit": "Hrs"}}, "Groups": [], "Estimated": false}" & @CRLF & _
"" & @CRLF & _
""
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