PHP: preg_match - "Delimiter must not be alphanumeric or backslash"

Question

Does anyone know what is wrong with this regex? It works fine on sites like RegexPal and RegExr, but in PHP it gives me this warning and no results:

Warning: preg_match() [function.preg-match]: Delimiter must not be alphanumeric or backslash

Here's my code:

preg_match('name="dsh" id="dsh" value="(.*?)"', 'name="dsh" id="dsh" value="123"', $matches);

Answer 1

You have no delimiter. Enclose the pattern in /

preg_match('/name="dsh" id="dsh" value="(.*?)"/', 'name="dsh" id="dsh" value="123"', $matches);

For patterns that include / on their own, it is advisable to use a different delimiter like ~ or # to avoid escaping:

// Delimited with # instead of /
preg_match('#name="dsh" id="dsh" value="(.*?)"#', 'name="dsh" id="dsh" value="123"', $matches);

Answer 2

You need delimiters:

preg_match('/name="dsh" id="dsh" value="(.*?)"/', 'name="dsh" id="dsh" value="123"', $matches);