Regular Expression within URL

Question

I've tried searching for the answer but it's a tough question to ask in the first place, here goes.

Consider the following URL(s):

• hotels-london-kensington-5star
• hotels-london-kensington-mayfair-5star
• hotels-london-5star

the following would be returned using the correct regular expression:

• london-kensington
• london-kensington-mayfair
• london

I'm trying to use regular expression to get the centre value(s) ONLY. I know the first and last words of the string in all cases ie 'hotels' (first) and '5star' (last).

UPDATE: I need to use regular expressions as the URL's are being routed through Codeigniters URI router. The centre part of the URI is dynamically built for search results.

Answer 1

Since you know the first and last words, you also know their lengths.

$out = substr($in,7,-6);

Or more generally:

$out = substr($in,strlen($begin),-strlen($end));

EDIT: If regex is required , just use /(?<=hotels-).*(?=-5star)/

Answer 2

For such simple cases you can use a explode()

$parts = explode('-', $string);
$wanted = array_slice($parts, 1, count($parts)-2);

Update: A regular expression. I still think it's easier to split the string into pieces manually.

~hotels-(.+)-5start~