using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?=
[ ]{0,8}? \d{1,9}
( .* ) $ # (1)
)
[ \d]{9}
(?= \1 $ )
";
string input = @"examples of valid strings
123456789
kfasdf 3456789asdf
a 1
and examples of invalid strings
12345 789
1 9
a 678a
";
RegexOptions options = RegexOptions.IgnorePatternWhitespace | 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