PHP-JSON数据解析

问题描述

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我有以下JSON数据.我需要用PHP编写一个函数，该函数接受一个categoryid并以数组形式返回属于它的所有URL.

I have the following JSON Data. I need help writing a function in PHP which takes a categoryid and returns all URLs belonging to it in an array.

类似这样的东西:

<?php
function returnCategoryURLs(catId)
{
    //Parse the JSON data here..
    return URLArray;
}
?>


{
    "jsondata": [
        {
            "categoryid": [
                20
            ],
            "url": "www.google.com"
        },
        {
            "categoryid": [
                20
            ],
            "url": "www.yahoo.com"
        },
        {
            "categoryid": [
                30
            ],
            "url": "www.cnn.com"
        },
        {
            "categoryid": [
                30
            ],
            "url": "www.time.com"
        },
        {
            "categoryid": [
                5,
                6,
                30
            ],
            "url": "www.microsoft.com"
        },
        {
            "categoryid": [
                30
            ],
            "url": "www.freshmeat.com"
        }
    ]
}

谢谢

推荐答案

这样的事情怎么样:

您首先使用 json_decode ，这是php的内置功能，可解码JSON数据:

You first use json_decode, which is php's built-in function to decode JSON data :

$json = '{
    ...
}';
$data = json_decode($json);

在这里，您可以看到什么样的PHP数据(即对象，数组等) JSON字符串的解码为您提供了例如，

Here, you can seen what PHP kind of data (i.e. objects, arrays, ...) the decoding of the JSON string gave you, using, for example :

var_dump($data);

然后，您遍历数据项，如果要搜索的$catId在列表中，则在每个元素的categoryid中搜索- in_array 可以帮助您做到这一点:

And, then, you loop over the data items, searching in each element's categoryid if the $catId you are searching for is in the list -- in_array helps doing that :

$catId = 30;
$urls = array();
foreach ($data->jsondata as $d) {
    if (in_array($catId, $d->categoryid)) {
        $urls[] = $d->url;
    }
}

而且，每次找到匹配项时，将url添加到数组中...

And, each time you find a match, add the url to an array...

这意味着，在循环结束时，您将获得URL列表:

Which means that, at the end of the loop, you have the list of URLs :

var_dump($urls);

在此示例中，给您:

array
  0 => string 'www.cnn.com' (length=11)
  1 => string 'www.time.com' (length=12)
  2 => string 'www.microsoft.com' (length=17)
  3 => string 'www.freshmeat.com' (length=17)

由您决定要从中构建-剩下的工作不多;-)

Up to you to build from this -- there shouldn't be much left to do ;-)

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