using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @".{30,}?\K\.(?=.{30,})";
string input = @"this is a long sentence. it contains full stops. I want to match the full stop after the halfway point.
this sentence is shorter. it also contains full stops.";
foreach (Match m in Regex.Matches(input, pattern))
{
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