- array_merge: documentation ( source)
- array_walk: documentation ( source)
<?php
$a = [['number'=>777]];
$b = [];
for ($i = 0; $i < 50; ++$i) {
//$b += $a;
$b = array_merge($a, $b);
$b[$i]['number'] = $i;
}
array_walk($b, function($val, $key) { echo '$b[' . $key . ']["number"] = ' . $val['number'] . PHP_EOL; });