Regular expression to use which matches text before .html and after /

Question

With this string

http://sfsdf.com/sdfsdf-sdfsdf/sdf-as.html

I need to get sdf-as

with this

hellow-1/yo-sdf.html

I need yo-sdf

Answer 1

This should get you want you need:

Regex re = new Regex(@"/([^/]*)\.html$");
Match match = re.Match("http://sfsdf.com/sdfsdf-sdfsdf/sdf-as.html");
Console.WriteLine(match.Groups[1].Value); //Or do whatever you want with the value

This needs using System.Text.RegularExpressions; at the top of the file to work.

Answer 2

using System.Text.RegularExpressions;
Regex pattern = new Regex(".*\/([a-z\-]+)\.html");
Match match = pattern.Match("http://sfsdf.com/sdfsdf-sdfsdf/sdf-as.html");
if (match.Success)
{
    Console.WriteLine(match.Value);
}
else
{
    Console.WriteLine("Not found :(");
}

Answer 3

Try this:

string url = "http://sfsdf.com/sdfsdf-sdfsdf/sdf-as.html";
Match match = Regex.Match(url, @"/([^/]+)\.html$");
if (match.Success)
{
    string result = match.Groups[1].Value;
    Console.WriteLine(result);
}

Result:

sdf-as

However it would be a better idea to use the System.URI class to parse the string so that you correctly handle things like http://example.com/foo.html?redirect=bar.html.

Answer 4

This one makes the slash and dot parts optional, and allows the file to have any extension:

new Regex(@"^(.*/)?(?<fileName>[^/]*?)(\.[^/.]*)?$", RegexOptions.ExplicitCapture);

But I still prefer Substring(LastIndexOf(...)) because it is far more readable.

Answer 5

There are many ways to do this. The following uses lookarounds to match only the filename portion. It actually allows no / if such is the case:

string[] urls = {
   @"http://sfsdf.com/sdfsdf-sdfsdf/sdf-as.html",
   @"hellow-1/yo-sdf.html",
   @"noslash.html",
   @"what-is/this.lol",
};

foreach (string url in urls) {
   Console.WriteLine("[" + Regex.Match(url, @"(?<=/|^)[^/]*(?=\.html$)") + "]");
}

This prints:

[sdf-as]
[yo-sdf]
[noslash]
[]

How the pattern works

There are 3 parts:

• (?<=/|^) : a positive lookbehind to assert that we're preceded by a slash /, or we're at the beginning of the string
• [^/]* : match anything but slashes
• (?=\.html$): a positive lookahead to assert that we're followed by ".html" (literally on the dot)

References

• regular-expressions.info/Lookarounds, Anchors

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A non-regex alternative

Knowing regex is good, and it can do wonderful things, but you should always know how to do basic string manipulations without it. Here's a non-regex solution:

static String getFilename(String url, String ext) {
   if (url.EndsWith(ext)) {
     int k = url.LastIndexOf("/");
     return url.Substring(k + 1, url.Length - ext.Length - k - 1);
   } else {
     return "";
   }
}

Then you'd call it as:

getFilename(url, ".html")

API links

• String.Substring, EndsWith, and LastIndexOf

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Attachments

• Source code and output on ideone.com