- print_r: documentation ( source)
- str_replace: documentation ( source)
- explode: documentation ( source)
- json_encode: documentation ( source)
<?php
$arr = array ( '0' => array("red","green"),
'1' => array("blue","yellow")
);
$res = explode(",",str_replace(array('[',']',':','}','{'),'',json_encode($arr)));
print_r($res);