- print_r: documentation ( source)
- array_merge: documentation ( source)
- array_fill: documentation ( source)
<?php
$my_array = ['a','b','c'];
$dyn_array = [1, 2, 3];
$num = 2;
$result = array_merge($my_array, ...array_fill(0, $num, $dyn_array));
print_r($result);