3v4l.org

run code in 300+ PHP versions simultaneously
<?php $blue = array(1,4,7,10); $red = array(2,3,5,6,8,9); $final_array = array(); $j = 0; for($i=0; $i<sizeof($blue); $i++) { $final_array[] = $blue[$i]; $r = $i*2; $p = $r+1; $final_array[] = $red[$r]; $final_array[] = $red[$p]; } echo '<pre>'; print_r($final_array);
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Warning: Undefined array key 6 in /in/UHNeU on line 14 Warning: Undefined array key 7 in /in/UHNeU on line 15 <pre>Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 [8] => 9 [9] => 10 [10] => [11] => )
Output for 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.25, 7.4.27 - 7.4.33
Notice: Undefined offset: 6 in /in/UHNeU on line 14 Notice: Undefined offset: 7 in /in/UHNeU on line 15 <pre>Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 [8] => 9 [9] => 10 [10] => [11] => )
Output for 7.3.32 - 7.3.33, 7.4.26
<pre>Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 [8] => 9 [9] => 10 [10] => [11] => )
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17
Notice: Undefined offset: 6 in /in/UHNeU on line 14 Notice: Undefined offset: 7 in /in/UHNeU on line 15 <pre>Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 [8] => 9 [9] => 10 [10] => [11] => )

preferences:
284.93 ms | 403 KiB | 457 Q