Online PHP editor | refs for fTheO

<?php $ages = [18,25,36,20,23,21,31]; $groups = array_count_values(array_map(function ($v) { return (int)($v / 10); }, $ages)); for ($i = 0; $i <= max(array_keys($groups)); $i++) { echo $i*10 . " to " . ($i*10+9) . " years: " . (isset($groups[$i]) ? $groups[$i]: 0) . "\n"; } for ($i = 0; $i <= max(array_keys($groups)); $i++) { if (isset($groups[$i])) echo $i*10 . " to " . ($i*10+9) . " years: " . $groups[$i] . "\n"; }