获取JSON的第一个条目

问题描述：

I have this JSON in a URL:

{"success":true,"rgInventory":{"6073259621":{"id":"6073259621","classid":"1660549198","instanceid":"188530139","amount":"1","pos":1}}}

I need obtain the first entry after rgInventory. The problem is the problem is that suppose that I don't know that there are "6073259621". How I can obtain it without know what there?

I try this but don't work:

$obj = json_decode(file_get_contents($url), true);
$obj2 = json_decode(json_encode($obj['rgInventory']), true);
$obj3 = json_decode(json_encode($obj2), true); 
echo $obj3;

我在URL中有这个JSON： p>

  {“ 成功 “：真实的，” rgInventory “：{” 6073259621 “：{” ID “：” 6073259621" ， “CLASSID”： “1660549198”， “实例id”： “188530139”， “量”： “1”， “POS”  ：1}}} 
  code>  pre> 
 
 我需要在 rgInventory  code>之后获取第一个条目。 问题是问题是假设我不知道有“6073259621” code>。 我怎么能在不知道是什么的情况下获得呢？ p> 
 
 
我试试这个但不起作用： p> 
 
 

  $ obj = json_decode（file_get_contents  （$ url），true）; 
 $ obj2 = json_decode（json_encode（$ obj ['rgInventory']），true）; 
 $ obj3 = json_decode（json_encode（$ obj2），true）;  
echo $ obj3; 
  code>  pre> 
  div>

答

Here's a simple way to get the key and the value (array) using each():

$data = json_decode(file_get_contents($url), true);

list($key, $val) = each($data['rgInventory']);

echo $key;
print_r($val);

Yields:

6073259621
Array
(
    [id] => 6073259621
    [classid] => 1660549198
    [instanceid] => 188530139
    [amount] => 1
    [pos] => 1
)

But I just noticed that the id is the same as the key, so not really needed.

答

if the JSON string is valid and like below

{ "success":true,
  "rgInventory":{
      "6073259621":{
          "id":"6073259621",
          "classid":"1660549198",
          "instanceid":"188530139",
          "amount":"1",
          "pos":1
       }
    }
}

get the decode in $obj like

  $obj = json_decode(file_get_contents($url), true);

then your first entry would be

 echo array_keys($obj['rgInventory'])[0];

to understand it clearly and to know where is "6073259621"

$obj = json_decode(file_get_contents($url), true);
var_dump($obj);

also note the difference

$json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';

var_dump(json_decode($json));
var_dump(json_decode($json, true));

the output would be ..

// decode as object
object(stdClass)#1 (5) {
    ["a"] => int(1)
    ["b"] => int(2)
    ["c"] => int(3)
    ["d"] => int(4)
    ["e"] => int(5)
}

// decode as array
array(5) {
    ["a"] => int(1)
    ["b"] => int(2)
    ["c"] => int(3)
    ["d"] => int(4)
    ["e"] => int(5)
}

答

After you have the JSON decoded with this:

$obj = json_decode(file_get_contents($url), true);

You can get the first item from rgInventory, regardless of what its key is, using reset.

$first_entry = reset($obj['rgInventory']);

获取JSON的第一个条目

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