从二维数组中娶某一列 转换成一维数组

5698, 'first_name' => 'Bill', 'last_name' => 'Gates', ), array( 'id' => 4767, 'first_name' => 'Steve', 'last_name' => 'Jobs', ), array( 'id' => 3809, 'first_name' => 'Mark', 'last_name' => 'Zuckerberg', ) ); $last_names = array_column($a, 'last_name'); print_r($last_names); ?>