- print_r: documentation ( source)
<?php
$blue = array(1,4,7,10);
$red = array(2,3,5,6,8,9);
$final_array = array();
$j = 0;
for($i=0; $i<sizeof($blue); $i++)
{
$final_array[] = $blue[$i];
$r = $i*2;
$p = $r+1;
$final_array[] = $red[$r];
$final_array[] = $red[$p];
}
echo '<pre>'; print_r($final_array);