1.二维数组转一维数组

示例

$records = array(
    array( 'id' => 2135, 'first_name' => 'John','last_name' => 'Doe', ),
    array('id' => 3245,'first_name' => 'Sally','last_name' => 'Smith', ),
    array('id' => 5342,'first_name' => 'Jane','last_name' => 'Jones',),
    array('id' => 5623,'first_name' => 'Peter','last_name' => 'Doe',)
);

(1).可以用foreach循环处理数组

foreach($msg as $k => $v){
          $ids[] = $id;
          $names[] = $name;
}

(2).用php函数处理

$last_names = array_column($records, 'last_name');
Array([45]=>jack，[34]=>mary，[78]=>lili)

$last_names = array_column($records, 'last_name', 'id');
Array( [2135] => Doe, [3245] => Smith, [5342] => Jones, [5623] => Doe)