using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?(DEFINE)
(?<lowercase>(?=[^a-z]*[a-z])) # lowercase
(?<uppercase>(?=[^A-Z]*[A-Z])) # uppercase
(?<anA>A(?=B))
)
^(?&lowercase)(.*?)((?&anA)).*";
string input = @"this is an A
A
ABC
";
RegexOptions options = RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace;
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