Online PHP editor | output for 63bU8

<?php $arrVal = array ( '22' => array( '0' => 60, '29' => array( '0' => 6 ), '30' => array ( '0' => 5, '1' => 8 ), '31' => array ( '0' => 7, '1' => 9, '2' => 14, '3' => 26 ) ), '23' => 12, '35' => 10, '42' => 22 ); //60[6][5||8][7||9||14||26]|12|10|22 $constructedValue = ""; echo $constructedValue = implodeMultiArr($arrVal); function implodeMultiArr($arrVal) { foreach ( $arrVal as $k=>$v) if ( is_array($v) ) { $constructedValue .= "[".implodeMultiArr($v)."]"; } else { return $constructedValue .= $v."||"; } } }