php - Yelp API 输出错误

Question

我正在尝试使用 Yelp API2 做一些事情

$response = json_decode($data);

它以 PHP 对象格式返回数据，如下所示:

stdClass Object
(
[region] => stdClass Object
    (
        [span] => stdClass Object
            (
                [latitude_delta] => 0.28083237848028
                [longitude_delta] => 0.23501544732261
            )

        [center] => stdClass Object
            (
                [latitude] => 31.335313781127
                [longitude] => -92.786144296672
            )

    )

[total] => 736
[businesses] => Array
    (
        [0] => stdClass Object
            (
                [is_claimed] => 1
                [rating] => 4
                [mobile_url] => http://m.yelp.com/bizzzz?utm_campaign=yelp_api&utm_medium=api_v2_search&utm_source=toQu_qgvu90-Z7dQuZOWMQ
                [rating_img_url] => https://s3-media4.fl.yelpcdn.com/assets/2/www/img/c2f3dd9799a5/ico/stars/v1/stars_4.png
                [review_count] => 147
                [name] => Name here
                [rating_img_url_small] => https://s3-media4.fl.yelpcdn.com/assets/2/www/img/f62a5be2f902/ico/stars/v1/stars_small_4.png
                [url] => http://www.yelp.com/biz/zzz?utm_campaign=yelp_api&utm_medium=api_v2_search&utm_source=toQu_qgvu90-Z7dQuZOWMQ
                [categories] => Array
                    (
                        [0] => Array
                            (
                                [0] => Chinese
                                [1] => chinese
                            )
                    )

                [phone] => 5123355555
                [snippet_text] => My family and I went to HAO-Q Asian Kitchen for the first time before a performance of our children in Aladdin.  We all happen really love Asian cuisine....
                [image_url] => https://s3-media3.fl.yelpcdn.com/bphoto/XS5NjGCdn3s14_efs9w5rw/ms.jpg
                [snippet_image_url] => http://s3-media4.fl.yelpcdn.com/photo/ZxVY3kdLGl6AyAblYbIRgQ/ms.jpg
                [display_phone] => +1-512-338-5555
                [rating_img_url_large] => https://s3-media2.fl.yelpcdn.com/assets/2/www/img/ccf2b76faa2c/ico/stars/v1/stars_large_4.png
                [id] => kitchen-austin
                [is_closed] => 
                [location] => stdClass Object
                    (
                        [city] => Austin
                        [display_address] => Array
                            (
                                [0] => 123 Street
                                [1] => Ste 113
                                [2] => Far West
                                [3] => Austin, TX 78731
                            )

                        [geo_accuracy] => 8
                        [neighborhoods] => Array
                            (
                                [0] => Far West/Northwest Hills
                            )

                        [postal_code] => 78731
                        [country_code] => US
                        [address] => Array
                            (
                                [0] => 3742 Far W Blvd
                                [1] => Ste 113
                            )

                        [coordinate] => stdClass Object
                            (
                                [latitude] => 31.356237
                                [longitude] => -92.758041
                            )

                        [state_code] => TX
                    )

            )

我想使用限制输出一些结果:

$limit = (isset($_POST['displayLimit']) ? $_POST['displayLimit'] : 10);

for ($x = 0; $x <= $limit; $x++) { 

}

输出很好，但对于循环的每次迭代和每个值，我也不断收到以下错误:

Notice: Undefined offset: 10 in /mypath/YelpTest.php on line 94 Notice: Trying to get property of non-object in /mypath/YelpTest.php on line 94

我在这样的线路上是:

echo $response->businesses[$x]->name;

我错过了什么？

Answer 1

您正试图从只有 9 个元素的数组中获取第 10 个元素；您不依赖于可能小于您的限制的目标数组大小。

如果我试图获取有限数量的记录，我会从 $response->businesses 中获取一个切片并通过该切片执行 foreach:

$limit = isset($_POST['displayLimit']) ? $_POST['displayLimit'] : 10;

foreach (array_slice($response->businesses, 0, $limit) as $business) {
    echo $business->name;
}

array_slice函数有一个很好的特性:当 $limit 大于数组元素的总数时(从 $offset 开始，函数的第二个参数)它只返回可用的元素.例如，如果您执行 array_slice([1, 2, 3, 4], 0, 100)，它会返回 [1, 2, 3, 4] — limit是100，但是array只有4个元素，所以全部返回，切片时没有向array添加任何元素。

另一种方式:

$limit = isset($_POST['displayLimit']) ? $_POST['displayLimit'] : 10;

$counter = 0;

foreach ($response->businesses as $business) {
    echo $business->name;

    $counter++;

    if ($counter >= $limit) {
        break;
    }
}

这里我只是在达到限制时中断 foreach 循环。当我的数组元素少于 $limit 时，我不会出错。

从您的代码继承的另一种方法:

$limit = isset($_POST['displayLimit']) ? $_POST['displayLimit'] : 10;

for ($x = 0; $x < $limit; $x++) {
    if (!array_key_exists($x, $request->businesses)) {
        // We have reached the end of $request->businesses array,
        // so break "for" loop.
        break;
    }

    echo $business->name;
}

在任何情况下，您都应该依赖数组的大小，因为它有可能小于 $limit，这会导致您出错。