为什么数组索引未定义未定义？

Question

I'm having trouble finding out why is the following code not working.

I've a JSON answer from a remote server, containting the following data:

...., "UserId":{"50423":"Free Kkludkjta","54379":"Sjkllyu\u00e9lkj Nolla","67103":"Tswt\u00f3 BLLA","64469":"Uz\u00e1h G","46699":"RT\u00e1sdt UTSF","46873":"Tam\u00e1s XXXX"}, ...

(names are swapped, but since there are some special chars in the aswer I've kept those)

And I have the following code sniplet, which gives 'array index undefined for idx 64469':

$proj_schema = json_decode($proj_schema);
                        var_dump($proj_schema->UserId);
                        $avail_users = (array)$proj_schema->UserId;
                        var_dump($avail_users);
                        var_dump($avail_users[64469]);

The output is the following:

C:\wamp\www\j34\administrator\components\com_mycomponent\views\myview\view.html.php:113:
object(stdClass)[309]
  public '50423' => string 'Name1' (length=14)
  public '54379' => string 'Name2' (length=18)
  public '67103' => string 'Name3' (length=12)
  public '64469' => string 'Name4' (length=15)
  public '46699' => string 'Name5' (length=11)
  public '46873' => string 'Name6' (length=12)

C:\wamp\www\j34\administrator\components\com_mycomponent\views\myview\view.html.php:115:
array (size=6)
  '50423' => string 'Name1' (length=14)
  '54379' => string 'Name2' (length=18)
  '67103' => string 'Name3' (length=12)
  '64469' => string 'Name4' (length=15)
  '46699' => string 'Name5' (length=11)
  '46873' => string 'Name6' (length=12)

Notice: Undefined offset: 64469 in C:\wamp\www\j34\administrator\components\com_mycomponent\views\myview\view.html.php on line 116

If I walk through the array with foreach and write out the element based on 'if ($key == 64469)' it echos the name, but I cannot access the name by array key.

Results are same with PHP 5.6.32 (I know) and PHP 7.1.0. Result is the same if I put the id in "" or '';

What am I missing with the casting?

Answer 1

You are using the JSON as an object and not as an array. Therefore, the key does not exist, because it is a property.

Decode with true as 2nd argument to get an array instead of an object.

$proj_schema = json_decode($proj_schema, true);