如何在PHP上创建带双引号的变量以post到API

$variable = "This is a string with double quotes.";

// 创建cURL资源
$curl = curl_init();

// 设置POST请求的URL
$url = "https://example.com/api";

// 设置POST请求的参数
$data = array(
    'variable' => $variable
);

// 将参数转换为JSON格式
$jsonData = json_encode($data);

// 设置cURL选项
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $jsonData);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);

// 发送请求并获取响应
$response = curl_exec($curl);

// 关闭cURL资源
curl_close($curl);

// 处理响应
if ($response === false) {
    echo "POST request failed.";
} else {
    echo "POST request successful. Response: " . $response;
}