array_column()在PHP中的實際應用案例

array_column() 是 PHP 5.5.0 及更高版本中的一個內置函數，它可以從多維數組或對象數組中提取一列數據

1. 獲取用戶名稱列表：

$users = [
    ['id' => 1, 'name' => 'Alice'],
    ['id' => 2, 'name' => 'Bob'],
    ['id' => 3, 'name' => 'Charlie']
];

$names = array_column($users, 'name');
print_r($names); // 輸出: Array ( [0] => Alice [1] => Bob [2] => Charlie )

2. 將用戶ID作為鍵值：

$users = [
    ['id' => 1, 'name' => 'Alice'],
    ['id' => 2, 'name' => 'Bob'],
    ['id' => 3, 'name' => 'Charlie']
];

$names = array_column($users, 'name', 'id');
print_r($names); // 輸出: Array ( [1] => Alice [2] => Bob [3] => Charlie )

3. 從對象數組中提取屬性：

class User {
    public $id;
    public $name;

    public function __construct($id, $name) {
        $this->id = $id;
        $this->name = $name;
    }
}

$users = [
    new User(1, 'Alice'),
    new User(2, 'Bob'),
    new User(3, 'Charlie')
];

$names = array_column($users, 'name');
print_r($names); // 輸出: Array ( [0] => Alice [1] => Bob [2] => Charlie )

4. 根據指定的鍵值對數組進行分組：

$users = [
    ['id' => 1, 'name' => 'Alice', 'group' => 'A'],
    ['id' => 2, 'name' => 'Bob', 'group' => 'B'],
    ['id' => 3, 'name' => 'Charlie', 'group' => 'A']
];

$groups = array_column($users, null, 'group');
print_r($groups);
/*
輸出:
Array
(
    [A] => Array
        (
            [id] => 3
            [name] => Charlie
            [group] => A
        )

    [B] => Array
        (
            [id] => 2
            [name] => Bob
            [group] => B
        )
)
*/

這些示例展示了如何使用 array_column() 函數處理不同類型的數組和對象。通過這個函數，你可以輕松地從復雜的數組結構中提取所需的數據。