Getting an ID out of a string. Regex problem.

Question

I am trying to get the ID from a URL string.

I'm trying with the following code:-

FROM:

<url>http://www.monkeys.com/monkey.php?id=24&lt;/url&gt;

I want to get '24' with:-

$ID = preg_replace($url, '/^<url>.*\?id=(.*)<\/url>$/', '\1');

Any help would be much appreciated - i'm sure this is a regular problem, but I find regex baffling.

Answer 1

you can use this regex:

/^[^?]+\?id=(.*).*$/

Answer 2

Regex is the wrong tool for the job. Use

• parse_str — Parses the string into variables and
• parse_url — Parse a URL and return its components

Example:

$url = "http://www.monkeys.com/monkey.php?id=24";
parse_str(parse_url($url, PHP_URL_QUERY), $parts);
var_dump( $parts ); // 24

Getting the URL out of the <URL> element should be trivial. DOM is your friend. See the various other questions dealing with Reading XML with PHP and also this article why you should not use Regex for parsing HTML.

Answer 3

If ID is numeric only :

/\?id=(\d+)/

If there's nothing after ID

/\?id=(.*)/