Question

What would be the best regular expression for this scenario?

Given this URL:

http://php.net/manual/en/function.preg-match.php

How should I go about selecting everything between (but not including) http://php.net and .php:

/manual/en/function.preg-match

This is for an Nginx configuration file.

Answer 1

Like this:

if (preg_match('/(?<=net).*(?=\.php)/', $subject, $regs)) {
    $result = $regs[0];
}

Explanation:

"
(?<=      # Assert that the regex below can be matched, with the match ending at this position (positive lookbehind)
   net       # Match the characters “net” literally
)
.         # Match any single character that is not a line break character
   *         # Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
(?=       # Assert that the regex below can be matched, starting at this position (positive lookahead)
   \.        # Match the character “.” literally
   php       # Match the characters “php” literally
)
"