using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        string input = ".BenefitLoadings[0].";

        var output = Test(input);

        for (int count = 0; count < output.Count; count++) 

            Console.WriteLine(output[count].Value);  

    }

    private static readonly Regex Pattern = new Regex(@"^BenefitLoadings\[\d\]$", RegexOptions.Compiled);

​

    public static MatchCollection  Test(string input)

    {

        return Pattern.Matches(input);

    }

}