using System;
using System.Text.RegularExpressions;
 
public class Test
{
	public static void Main()
	{
		string[] strings = { "LUB", "Pgm", "Regn", "Month", "Year", "Bywhat" };
 
		foreach (string s in strings)
        {
            string filter = @"[[LUB,=,COMMERCIAL],AND,[Pgm,=,PRIVATE],AND,[Regn,=,Rasna],AND,[Month,=,06],AND,[Year,=,2018],AND,[Bywhat,=,M]]";
			string pattern = string.Format(@"(?<=\[{0},=,)[^]\r\n]+(?=\])", s);
	        var m = Regex.Match(filter, pattern);
	        Console.WriteLine(m.Value);
        }
	}
}

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