一个非常好用的PHP数组函数

<?php
// Array representing a possible record set returned from a database
$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‘,
    )
);
 
$first_names = array_column($records, ‘first_name‘);
print_r($first_names);
?> 

Array
(
    [0] => John
    [1] => Sally
    [2] => Jane
    [3] => Peter
)

array_column($records, ‘last_name‘, ‘id‘);

Array
(
    [2135] => Doe
    [3245] => Smith
    [5342] => Jones
    [5623] => Doe
)