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

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);