how to get pattern from regex php code example

Example 1: find substring regx php

if (preg_match("/\bweb\b/i", "PHP is the web scripting language of choice.")) {
    echo "A match was found.";
} else {
    echo "A match was not found.";
}

Example 2: php preg_match

preg_match ( string $pattern , string $subject [, array &$matches [, int $flags = 0 [, int $offset = 0 ]]] ) : int