using System;
using System.Text.RegularExpressions;
 
public class Example
{
    public static void Main()
    {
        string input = @" adas ''[]'foo''[]' ''[]'daf''[]' a";
 
        foreach (Match m in FindString(input, "''[]'", RegexOptions.Multiline))
        {
            Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index);
        }
    }
 
    public static MatchCollection FindString(string input, string delimiter, RegexOptions regexOptions = RegexOptions.Multiline)
    {
        string pattern = string.Format("{0}(.*?){0}", Regex.Escape(delimiter));
        var rx = new Regex(pattern, regexOptions);
        return rx.Matches(input);
    }
}

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