using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"[\n\r].*(\d\.\s+)(?!.*[\n\r](\d\.\s+)).*((<br\s*\/?>){2})";
string input = @"<br><br><br>. Do not replace <br> here.
1. One
2. Two
3. Three<br><br><br>End of List. Replace first two <br> with \n
New line follows.
<br><br><br>. Do not replace <br> here.";
RegexOptions options = RegexOptions.Multiline;
foreach (Match m in Regex.Matches(input, pattern, options))
{
Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index);
}
}
}
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 C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx