Why does this PHP regular expression return 1?

Question

Why does the following regular function call return a value of 1 :

preg_match('<strong>', '<strong[\>\s]+')

According to the documentation , I would have thought they ought to be reversed.

Answer 1

<strong> is a regular expression with angle brackets as delimiters . The actual regex is just the strong part, which successfully matches against the subject string since it has no ^ and $ anchors.

This will fail:

preg_match('/<strong>/', '<strong[\>\s]+')