using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?=\d++[A-Za-z]+[\w@]+|[a-zA-Z]++[\w@]+)[\w@]{2,}";
string input = @"Should match:
h1DF346 123FE453 3f3g6hj7j5v3 hasdf@asdf r3 r@
Should not match:
555555 @ hello onlyletters Jan 123@ @@@";
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