PHP中的多维数组到单个数组

Question

我在PHP工作,所以我有一个像这样的数组,从这个数组我希望过滤器采取user_id到另一个数组,如下所示.

Array
(
    [0] => Array
        (
            [user_id] => 66
            [distance] => 0
        )

    [1] => Array
        (
            [user_id] => 68
            [distance] => 0
        )

    [2] => Array
        (
            [user_id] => 81
            [distance] => 0
        )

    [3] => Array
        (
            [user_id] => 65
            [distance] => 0.00010218008081861118
        )

)

我想要一个像这样的数组,

$user_id=array(66,68,81,65);

Answer 1

使用array_column()

返回表示输入数组中单个列的值数组.

<?php

$user_array = array(
                  0 => array('user_id' => 1, 'name' => 'Bob'),
                  1 => array('user_id' => 2, 'name' => 'John'),
                  2 => array('user_id' => 3, 'name' => 'Mary')
              );

$users = array_column($user_array, 'user_id');

print_r($users);

输出:

Array
(
   [0] => 1
   [1] => 2
   [2] => 3
)

Answer 2

$array您上面提供的多维数组在哪里：

$data = array();
foreach ($array as $item) {
    $data[] = $item['user_id'];
}
print_r($data);