Online PHP editor | perf for D0Rf3

<?php function gen() { $data = array(); $i = 0; for($i; $i < 10; $i++) { $data[$i] = array( 'indent' => 'test ' . $i, 'depth' => 1 ); } for($i; $i < 700; $i++) { $data[$i] = array( 'indent' => 'test ' . $i, 'depth' => 'x', 'parent_id' => rand(0, $i) ); } return $data; } echo serialize(gen()); /* $array = array( 55 => array( 'ident' => 'test 1', 'depth' => 1, ), 77 => array( 'parent_id' => 55, 'ident' => 'test 2', 'depth' => 2, ), 109 => array( 'parent_id' => 77, 'ident' => 'test 3', 'depth' => 3, ), 78 => array( 'parent_id' => 55, 'ident' => 'test 4', 'depth' => 2, ), 25 => array( 'ident' => 'test 5', 'depth' => 1, ) ); */ $array = unserialize('a:0:{}'); /* function v1($array) { foreach ($array as $key => &$sub) { if (isset($sub['parent_id'])) { $array[$sub['parent_id']]['children'][$key] = &$sub; } } unset($sub); // unset the reference to make sure to not overwrite it later... // now remove the entries with parents foreach ($array as $key => $sub) { if (isset($sub['parent_id'])) unset($array[$key]); } return $array; } function push_at_key($what, $what_key, $key, $array) { foreach($array as $k => $v) { if($key == $k) { $array[$k]['children'][$what_key] = $what; return $array; } } foreach($array as $k => $v) { $array[$k] = push_at_key($what, $what_key, $key, $v['children']); } return $array; } function v2($array) { $out = array(); foreach ($array as $key => $sub) { if(!isset($sub['parent_id'])) { $out[$key] = $sub; } else { $out = push_at_key($sub, $key, $sub['parent_id'], $out); } } return $out; } //var_dump(v1($array)); //var_dump(v2($array)); */

Version	System time (s)	User time (s)	Memory (MiB)
7.2.10	0.016	0.006	15.20
7.2.9	0.103	0.003	15.15
7.2.8	0.131	0.010	15.30
7.2.7	0.109	0.003	15.35
7.2.6	0.111	0.010	15.26
7.2.5	0.118	0.007	15.47
7.2.4	0.163	0.000	15.32
7.1.22	0.117	0.003	14.14
7.1.21	0.095	0.006	14.09
7.1.20	0.128	0.010	14.34
7.1.19	0.121	0.003	14.04
7.1.18	0.132	0.010	14.21
7.1.17	0.026	0.013	14.21
7.0.31	0.123	0.006	13.77
7.0.30	0.104	0.007	13.79
5.6.38	0.013	0.007	15.23
5.6.37	0.008	0.008	15.41
5.6.36	0.005	0.008	15.25