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<?php $re = '/^(?\'a\'1?[0-9]?[0-9]|2[0-4][0-9]|25[0-5])\.(?&a)$/m'; $str = '255.255'; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);
Output for 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
array(1) { [0]=> array(3) { [0]=> string(7) "255.255" ["a"]=> string(3) "255" [1]=> string(3) "255" } }
Output for 7.1.25 - 7.1.33, 7.2.0 - 7.2.33
array(0) { }
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