聊聊php中二维数组的转化方法

$arr = array(
  array(1,2,3),
  array(4,5,6),
  array(7,8,9)
);

//将二维数组转化为一维数组
$new_arr = array_reduce($arr, 'array_merge', array());
print_r($new_arr);

Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 [8] => 9 )

$arr1 = array(
  array(1,2,3),
  array(4,5,6)
);
 
$arr2 = array(
  array(7,8,9),
  array(10,11,12)
);
 
//按行合并两个二维数组
$new_arr = array_merge($arr1, $arr2);
print_r($new_arr);

Array
(
    [0] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )
 
    [1] => Array
        (
            [0] => 4
            [1] => 5
            [2] => 6
        )
 
    [2] => Array
        (
            [0] => 7
            [1] => 8
            [2] => 9
        )
 
    [3] => Array
        (
            [0] => 10
            [1] => 11
            [2] => 12
        )
)

$arr = array(
  array('id'=>1, 'name'=>'Tom', 'age'=>25),
  array('id'=>2, 'name'=>'Jack', 'age'=>30),
  array('id'=>3, 'name'=>'Mike', 'age'=>35)
);
 
//将二维数组转化为json格式
$json_str = json_encode($arr);
echo $json_str;

[
    {"id":1,"name":"Tom","age":25},
    {"id":2,"name":"Jack","age":30},
    {"id":3,"name":"Mike","age":35}
]