using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"<url>\s*
(?>
(?>
(?><lastmod>\s*(?<mod>[^<]+)\s*</lastmod>)
|
(?><changefreq>\s*(?<freq>\w+)\s*</changefreq>)
|
(?><priority>\s*(?<prio>[01](?>\.\d{1,2})?)\s*</priority>)
)\s*
){0,3}\s*
<loc>\s*
(?<uri>[^<]+)\s*
</loc>\s*
(?>
(?>
(?><lastmod>\s*(?<mod>[^<]+)\s*</lastmod>)
|
(?><changefreq>\s*(?<freq>\w+)\s*</changefreq>)
|
(?><priority>\s*(?<prio>[01](?>\.\d{1,2})?)\s*</priority>)
)\s*
){0,3}\s*
</url>";
string input = @"<?xml version=""1.0"" encoding=""UTF-8""?>
<urlset xmlns=""http://www.sitemaps.org/schemas/sitemap/0.9"">
<url>
<lastmod>2005-01-01</lastmod>
<changefreq>monthly</changefreq>
<priority>0.8</priority>
<loc>http://www.example.com/</loc>
</url>
<url>
<loc>http://www.example.com/catalog?item=12&desc=vacation_hawaii</loc>
<changefreq>weekly</changefreq>
</url>
<url>
<loc>http://www.example.com/catalog?item=73&desc=vacation_new_zealand</loc>
<lastmod>2004-12-23</lastmod>
<changefreq>weekly</changefreq>
</url>
<url>
<loc>http://www.example.com/catalog?item=74&desc=vacation_newfoundland</loc>
<lastmod>2004-12-23T18:00:15+00:00</lastmod>
<priority>0.3</priority>
</url>
<url>
<loc>http://www.example.com/catalog?item=83&desc=vacation_usa</loc>
<lastmod>2004-11-23</lastmod>
</url>
</urlset>";
RegexOptions options = RegexOptions.IgnorePatternWhitespace | RegexOptions.CultureInvariant;
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