Online PHP editor | output for sJWmA

@ 2016-07-27T15:22:53Z

<?php
$pattern = [];
for ($i = 0; $i < 300; $i++) {
    $pattern[] = "(?'group{$i}'{$i}$)";
}

$fullPattern = '/' . implode('|', $pattern) . '/uix';

preg_match($fullPattern, '290', $matches);
var_dump(isset($matches['group253']));
var_dump(isset($matches['group254']));
var_dump(isset($matches['group255']));

var_dump($matches['group290']);
var_dump($matches['group291']);

Output for 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: bool(true) bool(true) bool(true) string(3) "290" Warning: Undefined array key "group291" in /in/sJWmA on line 15 NULL
Output for 5.6.25, 7.0.10 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.33: bool(true) bool(true) bool(true) string(3) "290" Notice: Undefined index: group291 in /in/sJWmA on line 15 NULL
Output for 7.3.32 - 7.3.33: bool(true) bool(true) bool(true) string(3) "290" NULL
Output for 5.6.0 - 5.6.24, 7.0.0 - 7.0.9: bool(true) bool(false) bool(true) string(0) "" string(3) "290"

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