using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var debugData = "2023-01-03T20:56:44-08:00 d2096c3a4c57d5810b050105072942f112d0e459; House; aether://experiments/a8f4f398-1d65-4ee3-b557-227affd1acb5; node id 87b44048; graph @@GraphInput@@; target='ELV-XML' market='UAS-SAD' env='default'";

        var market = ExtractMarket(debugData);

        Console.WriteLine(market);

    }

    private static string ExtractMarket(string debugData)

        {

            if (!string.IsNullOrEmpty(debugData))

            {

                return "";

            }

            var match = Regex.Match(debugData, @"market='[a-zA-Z]*");

            if (!match.Success)

            {

                return "";

            }

            Console.WriteLine(market);

​

            var market = match.Value;

            match = Regex.Match(market, @"'.*'");

            if (!match.Success)

            {

                return "";

            }

            market = match.Value;

​

            if (market.Length < 2)

            {

                return "";

            }

​

            // remove surrounded ' from market

            market = market.Substring(1, market.Length - 2);

            return market;

        }

}