PHP5.5发布了，其中增加了一个新的数组函数array_column，感觉不错的！但是低版本PHP要使用，得自己实现：
参考地址：https://wiki.php.net/rfc/array_column

复制代码 代码如下:
if(!function_exists("array_column")){
    function array_column($input, $columnKey, $indexKey=null){
        $columnKeyIsNumber      = (is_numeric($columnKey)) ? true : false;
        $indexKeyIsNull         = (is_null($indexKey)) ? true : false;
        $indexKeyIsNumber       = (is_numeric($indexKey)) ? true : false;
        $result                 = array();
        foreach((array)$input as $key=>$row){
            if($columnKeyIsNumber){
                $tmp            = array_slice($row, $columnKey, 1);
                $tmp            = (is_array($tmp) && !empty($tmp)) ? current($tmp) : null;
            }else{
                $tmp            = isset($row[$columnKey]) ? $row[$columnKey] : null;
            }
            if(!$indexKeyIsNull){
                if($indexKeyIsNumber){
                    $key        = array_slice($row, $indexKey, 1);
                    $key        = (is_array($key) && !empty($key)) ? current($key) : null;
                    $key        = is_null($key) ? 0 : $key;
                }else{
                    $key        = isset($row[$indexKey]) ? $row[$indexKey] : 0;
                }
            }
            $result[$key]       = $tmp;
        }
        return $result;
    }
} // 使用例子
$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"
    )
);
$firstNames = array_column($records, "first_name");
print_r($firstNames);
/*
Array
(
    [0] => John
    [1] => Sally
    [2] => Jane
    [3] => Peter
)
*/$records = array(
    array(1, "John", "Doe"),
    array(2, "Sally", "Smith"),
    array(3, "Jane", "Jones")
);
$lastNames = array_column($records, 2);
print_r($lastNames);
/*
Array
(
    [0] => Doe
    [1] => Smith
    [2] => Jones
)
*/$mismatchedColumns = array(
    array(
        "a" => "foo",
        "b" => "bar",
        "e" => "baz"
    ),
    array(
        "a" => "qux",
        "c" => "quux",
        "d" => "corge"
    ),
    array(
        "a" => "grault",
        "b" => "garply",
        "e" => "waldo"
    ),
);
$foo = array_column($mismatchedColumns, "a", "b");
print_r($foo);
/*
Array
(
    [bar] => foo
    [0] => qux
    [garply] => grault
)
*/

array_column 用于获取二维数组中的元素(PHP 5 >= 5.5.0)
复制代码 代码如下:
<?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
)<?php
// Using the $records array from Example #1
$last_names = array_column($records, "last_name", "id");
print_r($last_names);
?>
Array
(
    [2135] => Doe
    [3245] => Smith
    [5342] => Jones
    [5623] => Doe
)