using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?m)^([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Za-z][0-9]{1,2})|(([AZa-z][0-9][A-Za-z])|([A-Za-z][A-Za-z][0-9][A-Za-z]?)))? ?[0-9][A-Za-z]{2}$";
string substitution = @"$0@";
string input = @"Ivy Cottage, Rockley,SN81RT
11 Brabourne Gardens, North Shields,NE299JB
2 Russell Gardens, Whitchurch,RG287AY
14 Red Barns, Newcastle Upon Tyne,NE12TP
1 Hollybank, Tamworth Road, Lichfield,WS149JE
69 Burnlee Road, Holmfirth,HD92PS
30 Cashio Lane, Letchworth Garden City,SG61AX
14 Cedartree Gardens, Whitley Bay,NE258XN
518A Victoria Road, Ruislip,HA40HD
9 Pear Avenue, Leeds,LS168GT
";
RegexOptions options = RegexOptions.Multiline;
Regex regex = new Regex(pattern, options);
string result = regex.Replace(input, substitution);
}
}
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