3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = ['coke.', 'fanta.', 'chocolate.', 'a.', 'b.', 'c.', 'd.']; $result = array_reduce($array, function($c, $i) { if ( strlen(end($c)) < 6 ) $c[key($c)] .= empty(current($c)) ? $i : " $i"; else $c[] = $i; return $c; }, ['']); print_r($result);
Output for 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.7
Array ( [0] => coke. fanta. [1] => chocolate. [2] => a. b. c. [3] => d. )

preferences:
243.59 ms | 404 KiB | 300 Q