php数组

Question

Array
(
    [321] => Array
        (
            [quantity] => 11
            [res] => re11
        )    [345] => Array
        (
            [quantity] => 22
            [res] => re22
        )    [346] => Array
        (
            [quantity] => 33
            [res] => re33
        ))
上面数组,怎么把321,345,346取出来赋给 $arr,即$arr= '321,345,346';
请教了...

Answer 1

array_keys — 以数组形式返回输入数组中所有的键名