数组遍历有关问题

$arr=array(
	'10'=>array(
		'12'=>0
	),
	'15'=>array(
		'30'=>array(
			'35'=>0
		),
		'31'=>array(
			'40'=>0
		)
	)
)

$a[]='10,12';
$a[]='15,30,35';
$a[]='15,31,40';

$arr=array('10'=>array('12'=>0),'15'=>array('30'=>array('35'=>0),'31'=>array('40'=>0)));		
		$a=array();
		foreach ($arr as $k=>$v){
			$a[$k][]=$k;
			if(is_array($v)){
				foreach ($v as $kk=>$vv){
					$a[$k][]=$kk;
				}
			}		
		}
		var_dump($a);

$arr=array('10'=>array('12'=>0),'15'=>array('30'=>array('35'=>0),'31'=>array('40'=>0),'33'=>array('42'=>0)));		
		$a=array();
		$i=0;
		foreach ($arr as $k=>$v){			
			$a[$i][]=$k;
			if(is_array($v)){
				foreach ($v as $kk=>$vv){
					$a[$i][]=$kk;
					if(is_array($vv)){
						foreach ($vv as $kkk=>$vvv){
							$j=0;
							if($j==0){
								unset($a[$i]);
								$a[$i.'-'.$i][]=$k;
								$a[$i.'-'.$i][]=$kk;
								$a[$i.'-'.$i][]=$kkk;
							}else{
								$a[$i][]=$kkk;
							}
						}
					}
					$i++;
				}
			}
			$i++;
		}
		var_dump($a);

最后是这样
$arr=array('10'=>array('12'=>0),'15'=>array('30'=>array('35'=>0),'31'=>array('40'=>0),'33'=>array('42'=>0)));		
		$a=array();
		$i=0;
		foreach ($arr as $k=>$v){			
			$a[$i][]=$k;
			if(is_array($v)){
				foreach ($v as $kk=>$vv){
					$a[$i][]=$kk;
					if(is_array($vv)){
						foreach ($vv as $kkk=>$vvv){							
							unset($a[$i]);
							$a[$i.'-'.$i][]=$k;
							$a[$i.'-'.$i][]=$kk;
							$a[$i.'-'.$i][]=$kkk;
						}
					}
					$i++;
				}
			}
		}
		var_dump(array_values($a));

$arr=array(
  '10'=>array(
    '12'=>0
  ),
  '15'=>array(
    '30'=>array(
      '35'=>0
    ),
    '31'=>array(
      '40'=>0
    )
  )
);

print_r(foo($arr));

function foo($ar) {
  $res = array();
  foreach($ar as $k=>$v) {
    if(is_array($v)) {
      foreach(foo($v) as $r) $res[] = "$k,$r";
    }else $res[] = $k;
  }
  return $res;
}

Array
(
    [0] => 10,12
    [1] => 15,30,35
    [2] => 15,31,40
)

$arr=array(
    '10'=>array(
        '12'=>0,
        '13'=>array(
            '14' => 0,
            '16' => array(
                '17' =>0
            )
        )
    ),
    '15'=>array(
        '30'=>array(
            '35'=>0
        ),
        '31'=>array(
            '40'=>0
        )
    )
);

function foo( $arr, &$str = '' )
{
    foreach($arr as $key => $value)
    {
        $str .= "," . $key;
        if(is_array($value))
        {
            foo($value, $str);

        }else{
            print_r( ltrim($str,',') );
            echo '
';
        }
        $str = rtrim( $str, ','.$key);
    }

}

foo($arr);

$arr=array(
    '10'=>array(
        '12'=>0,
        '13'=>array(
            '14' => 0,
            '16' => array(
                '17' =>0
            )
        )
    ),
    '15'=>array(
        '30'=>array(
            '35'=>0
        ),
        '31'=>array(
            '40'=>0
        )
    )
);

function foo( $arr, &$str = '' )
{
    foreach($arr as $key => $value)
    {
        $str .= "," . $key;
        if(is_array($value))
        {
            foo($value, $str);

        }else{
            print_r( ltrim($str,',') );
            echo '
';
        }
        $str = rtrim( $str, ','.$key);
    }

}

foo($arr);

$arr=array(
    '10'=>array(
        '12'=>0,
        '13'=>array(
            '14' => 0,
            '16' => array(
                '17' =>0
            )
        )
    ),
    '15'=>array(
        '30'=>array(
            '35'=>0
        ),
        '31'=>array(
            '40'=>0
        )
    )
);

function foo( $arr, &$str = '' )
{
    foreach($arr as $key => $value)
    {
        $str .= "," . $key;
        if(is_array($value))
        {
            foo($value, $str);

        }else{
            print_r( ltrim($str,',') );
            echo '
';
        }
        $str = rtrim( $str, ','.$key);
    }

}

foo($arr);

$arr=array(
  '10'=>array(
    '12'=>0
  ),
  '15'=>array(
    '30'=>array(
      '35'=>0
    ),
    '31'=>array(
      '40'=>0
    )
  )
);
function my($arr,$pid=10){
    static $item=array();
    static $s='';
    foreach($arr as $k=>$v){
         if(is_array($v)){
            foreach($v as $key=>$value){
                $s.=$key.',';
                if(is_array($value)){
                    my($value,$k);
                }
            }
         }else{
            $s.=$k;
         }
         $s=$pid.','.$s;
         $item[]=$s;
         $s='';
    }
    return $item;
}
$arr=my($arr);
array_pop($arr);
print_r($arr);

Array
(
    [0] => 10,12,
    [1] => 15,30,35
    [2] => 15,31,40
)