So bestimmen Sie den Typ der PHP-Funktionsparameter

if (is_int($param)) {
    // 参数是整数
} elseif (is_string($param)) {
    // 参数是字符串
} elseif (is_array($param)) {
    // 参数是数组
}

function calculate_total($products) {
    $total = 0;

    if (!is_array($products)) {
        throw new InvalidArgumentException("Product list must be an array");
    }

    foreach ($products as $product) {
        if (!is_array($product) || !array_key_exists('price', $product)) {
            throw new InvalidArgumentException("Invalid product format");
        }

        $total += $product['price'];
    }

    return $total;
}

// 使用函数
$products = [
    ['price' => 10],
    ['price' => 15]
];
$total = calculate_total($products);
echo "Total: $total";

function calculate_total(array $products) {
    // 参数被提示为数组
}

function calculate_total(array $products): float {
    // 参数被提示为数组并且返回值被提示为浮点数

    $total = 0;
    foreach ($products as $product) {
        $total += $product['price'];
    }

    return $total;
}

// 使用函数
$products = [
    ['price' => 10],
    ['price' => 15]
];
$total = calculate_total($products);
echo "Total: $total";