- array_chunk: documentation ( source)
- str_repeat: documentation ( source)
- implode: documentation ( source)
<?php
$array = [
'a' , 'b', 'c',
'd' , 'e', 'f',
'g' , 'h', 'i',
'j' , 'k', 'l',
'm' , 'n', 'o',
'p' , 'q', 'r'
];
foreach (array_chunk($array, 4) as $row) {
echo '<tr><td>' , implode('</td><td>', $row) , '</td>' , str_repeat('<td></td>', 4-count($row)) , '</tr>';
echo "\n";
}