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<?php $array = [ '1.1', '1.2', '1.3', '2.1', '2.2', '2.3', '3.1', '3.2', ]; $result = []; foreach ($array as $v) { sscanf($v, '%d', $major); if (!isset($ref[$major])) { $result[] = &$ref[$major]; } $ref[$major][] = $v; } var_export($result);
Output for 8.0.1 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.7
array ( 0 => array ( 0 => '1.1', 1 => '1.2', 2 => '1.3', ), 1 => array ( 0 => '2.1', 1 => '2.2', 2 => '2.3', ), 2 => array ( 0 => '3.1', 1 => '3.2', ), )

preferences:
113.61 ms | 402 KiB | 91 Q