PHP多维数组怎么遍历_PHP多维数组遍历方法与代码示例

// 示例1: 遍历一个已知深度的多维数组
$products = [
    'electronics' => [
        'phones' => ['iPhone 13', 'Samsung Galaxy S22'],
        'laptops' => ['MacBook Pro', 'Dell XPS 15']
    ],
    'clothing' => [
        'men' => ['T-shirt', 'Jeans'],
        'women' => ['Dress', 'Skirt']
    ]
];

echo "--- 嵌套 foreach 遍历商品 ---\n";
foreach ($products as $category => $subCategories) {
    echo "Category: " . $category . "\n";
    if (is_array($subCategories)) { // 确保是数组才继续遍历
        foreach ($subCategories as $type => $items) {
            echo "  Type: " . $type . "\n";
            if (is_array($items)) { // 再次检查
                foreach ($items as $item) {
                    echo "    - " . $item . "\n";
                }
            } else {
                echo "    - " . $items . "\n"; // 如果items不是数组，直接打印
            }
        }
    } else {
        echo "  Item: " . $subCategories . "\n"; // 如果subCategories不是数组，直接打印
    }
}

// 示例2: 使用递归函数遍历任意深度多维数组
$complexData = [
    'user' => [
        'id' => 101,
        'name' => 'Alice',
        'contact' => [
            'email' => 'alice@example.com',
            'phone' => '123-456-7890',
            'address' => [
                'street' => '123 Main St',
                'city' => 'Anytown',
                'zip' => '12345'
            ]
        ],
        'roles' => ['admin', 'editor']
    ],
    'settings' => [
        'theme' => 'dark',
        'notifications' => true
    ]
];

echo "\n--- 递归函数遍历复杂数据 ---\n";
function recursiveArrayTraverse($array, $indent = 0) {
    foreach ($array as $key => $value) {
        echo str_repeat("  ", $indent) . "Key: " . $key;
        if (is_array($value)) {
            echo " (Array)\n";
            recursiveArrayTraverse($value, $indent + 1); // 递归调用
        } else {
            echo ", Value: " . $value . "\n";
        }
    }
}
recursiveArrayTraverse($complexData);

// 示例3: 使用 array_walk_recursive
echo "\n--- array_walk_recursive 遍历 ---\n";
function printLeafItem($item, $key) {
    echo "  Leaf Key: {$key}, Value: {$item}\n";
}
array_walk_recursive($complexData, 'printLeafItem');

// 示例: 筛选出所有状态为 'active' 的用户
$users = [
    ['id' => 1, 'name' => 'Alice', 'status' => 'active'],
    ['id' => 2, 'name' => 'Bob', 'status' => 'inactive'],
    ['id' => 3, 'name' => 'Charlie', 'status' => 'active', 'details' => ['age' => 30]],
];

echo "\n--- 筛选 'active' 状态的用户 ---\n";
$activeUsers = [];
foreach ($users as $user) {
    // 检查是否存在 'status' 键且其值为 'active'
    if (isset($user['status']) && $user['status'] === 'active') {
        $activeUsers[] = $user;
    }
}
print_r($activeUsers);

// 更深层次的筛选，例如筛选年龄大于25的用户
$filteredByAge = [];
function filterUsersByAge($data, $minAge) {
    $result = [];
    foreach ($data as $item) {
        if (is_array($item)) {
            // 检查 details 数组和 age 键
            if (isset($item['details']['age']) && $item['details']['age'] > $minAge) {
                $result[] = $item;
            }
            // 如果内部还有数组，可以递归处理，这里简化为只检查一层
        }
    }
    return $result;
}
echo "\n--- 筛选年龄大于 25 的用户 ---\n";
print_r(filterUsersByAge($users, 25));

// 示例: 将所有 'inactive' 状态改为 'pending'
$usersToModify = [
    ['id' => 1, 'name' => 'Alice', 'status' => 'active'],
    ['id' => 2, 'name' => 'Bob', 'status' => 'inactive'],
    ['id' => 3, 'name' => 'Charlie', 'status' => 'active'],
];

echo "\n--- 将 'inactive' 状态改为 'pending' ---\n";
foreach ($usersToModify as &$user) { // 注意这里的 & 符号，表示引用
    if (isset($user['status']) && $user['status'] === 'inactive') {
        $user['status'] = 'pending';
    }
}
unset($user); // 最佳实践：解除引用，避免后续意外修改
print_r($usersToModify);

// 示例: 递归修改多维数组中所有 'price' 字段的值，增加10%
$productsWithPrices = [
    'books' => [
        ['title' => 'PHP Basics', 'price' => 20.00],
        ['title' => 'Advanced PHP', 'price' => 35.50]
    ],
    'courses' => [
        'online' => [
            ['name' => 'Web Dev', 'price' => 199.99],
            ['name' => 'Data Science', 'price' => 299.00]
        ]
    ]
];

echo "\n--- 递归修改所有 'price' 字段，增加10% ---\n";
function increasePricesRecursive(&$array, $percentage) {
    foreach ($array as $key => &$value) {
        if ($key === 'price' && is_numeric($value)) {
            $value *= (1 + $percentage / 100);
        } elseif (is_array($value)) {
            increasePricesRecursive($value, $percentage); // 递归调用
        }
    }
}
increasePricesRecursive($productsWithPrices, 10);
print_r($productsWithPrices);