不能使用 stdClass 类型的对象作为数组？

Question

I get a strange error using json_decode() . It decode correctly the data (I saw it using print_r ), but when I try to access to info inside the array I get:

Fatal error: Cannot use object of type stdClass as array in
C:\Users\Dail\software\abs.php on line 108

I only tried to do: $result['context'] where $result has the data returned by json_decode()

How can I read values inside this array?

Answer 1

使用json_decode的第二个参数使其返回一个数组：

$result = json_decode($data, true);

Answer 2

The function json_decode() returns an object by default.

You can access the data like this:

var_dump($result->context);

If you have identifiers like from-date (the hyphen would cause a PHP error when using the above method) you have to write:

var_dump($result->{'from-date'});

If you want an array you can do something like this:

$result = json_decode($json, true);

Or cast the object to an array:

$result = (array) json_decode($json);

Answer 3

You must access it using -> since its an object.

Change your code from:

$result['context'];

To:

$result->context;

Answer 4

Use true as the second parameter to json_decode . This will decode the json into an associative array instead of stdObject instances:

$my_array = json_decode($my_json, true);

See the documentation for more details.

Answer 5

Have same problem today, solved like this:

If you call json_decode($somestring) you will get an Object and you need to access like $object->key , but if u call json_decode($somestring, true) you will get an dictionary and can access like $array['key']

Answer 6

It's not an array, it's an object of type stdClass.

You can access it like this:

echo $oResult->context;

More info here: What is stdClass in PHP?

Answer 7

As the Php Manual say,

print_r — Prints human-readable information about a variable

When we use json_decode(); , we get an object of type stdClass as return type. The arguments, which are to be passed inside of print_r() should either be an array or a string. Hence, we cannot pass an object inside of print_r() . I found 2 ways to deal with this.

1. Cast the object to array.
   This can be achieved as follows.

    $a = (array)$object;

2. By accessing the key of the Object
   As mentioned earlier, when you use json_decode(); function, it returns an Object of stdClass. you can access the elements of the object with the help of -> Operator.

    $value = $object->key;

One, can also use multiple keys to extract the sub elements incase if the object has nested arrays.

$value = $object->key1->key2->key3...;

Their are other options to print_r() as well, like var_dump(); and var_export();

PS : Also, If you set the second parameter of the json_decode(); to true , it will automatically convert the object to an array();
Here are some references:
http://php.net/manual/en/function.print-r.php
http://php.net/manual/en/function.var-dump.php
http://php.net/manual/en/function.var-export.php

Answer 8

To get an array as result from a json string you should set second param as boolean true.

$result = json_decode($json_string, true);
$context = $result['context'];

Otherwise $result will be an std object. but you can access values as object.

  $result = json_decode($json_string);
 $context = $result->context;

Answer 9

Sometimes when working with API you simply want to keep an object an object. To access the object that has nested objects you could do the following:

We will assume when you print_r the object you might see this:

print_r($response);

stdClass object
(
    [status] => success
    [message] => Some message from the data
    [0] => stdClass object
        (
            [first] => Robert
            [last] => Saylor
            [title] => Symfony Developer
        )
    [1] => stdClass object
        (
            [country] => USA
        )
)

To access the first part of the object:

print $response->{'status'};

And that would output "success"

Now let's key the other parts:

$first = $response->{0}->{'first'};
print "First name: {$first}<br>";

The expected output would be "Robert" with a line break.

You can also re-assign part of the object to another object.

$contact = $response->{0};
print "First Name: " . $contact->{'first'} . "<br>";

The expected output would be "Robert" with a line break.

To access the next key "1" the process is the same.

print "Country: " . $response->{1}->{'country'} . "<br>";

The expected output would be "USA"

Hopefully this will help you understand objects and why we want to keep an object an object. You should not need to convert an object to an array to access its properties.

Answer 10

Try something like this one!

Instead of getting the context like: (this works for getting array index's)

$result['context']

try (this work for getting objects)

$result->context

Other Example is: (if $result has multiple data values)

Array
(
    [0] => stdClass Object
        (
            [id] => 15
            [name] => 1 Pc Meal
            [context] => 5
            [restaurant_id] => 2
            [items] => 
            [details] => 1 Thigh (or 2 Drums) along with Taters
            [nutrition_fact] => {"":""}
            [servings] => menu
            [availability] => 1
            [has_discount] => {"menu":0}
            [price] => {"menu":"8.03"}
            [discounted_price] => {"menu":""}
            [thumbnail] => YPenWSkFZm2BrJT4637o.jpg
            [slug] => 1-pc-meal
            [created_at] => 1612290600
            [updated_at] => 1612463400
        )

)

Then try this:

foreach($result as $results)
{
      $results->context;
}

Answer 11

You can convert stdClass object to array like:

$array = (array)$stdClass;

stdClsss to array

Answer 12

当您尝试将其作为$result['context'] ，您将其视为一个数组，它告诉您实际上正在处理一个对象的错误，那么您应该将其作为$result->context

Answer 13

Here is the function signature:

mixed json_decode ( string $json [, bool $assoc = false [, int $depth = 512 [, int $options = 0 ]]] )

When param is false, which is default, it will return an appropriate php type. You fetch the value of that type using object.method paradigm.

When param is true, it will return associative arrays.

It will return NULL on error.

If you want to fetch value through array, set assoc to true.

Answer 14

I got this error out of the blue because my facebook login suddently stopped working (I had also changed hosts) and throwed this error. The fix is really easy

The issue was in this code

  $response = (new FacebookRequest(
    FacebookSession::newAppSession($this->appId, $this->appSecret),
    'GET',
    '/oauth/access_token',
    $params
  ))->execute()->getResponse(true);

  if (isset($response['access_token'])) {       <---- this line gave error
    return new FacebookSession($response['access_token']);
  }

Basically isset() function expect an array but instead it find an object. The simple solution is to convert PHP object to array using (array) quantifier. The following is the fixed code.

  $response = (array) (new FacebookRequest(
    FacebookSession::newAppSession($this->appId, $this->appSecret),
    'GET',
    '/oauth/access_token',
    $params
  ))->execute()->getResponse(true);

Note the use off array() quantifier in first line.

Answer 15

instead of using the brackets use the object operator for example my array based on database object is created like this in a class called DB:

class DB {
private static $_instance = null;
private $_pdo,
        $_query, 
        $_error = false,
        $_results,
        $_count = 0;



private function __construct() {
    try{
        $this->_pdo = new PDO('mysql:host=' . Config::get('mysql/host') .';dbname=' . Config::get('mysql/db') , Config::get('mysql/username') ,Config::get('mysql/password') );


    } catch(PDOException $e) {
        $this->_error = true;
        $newsMessage = 'Sorry.  Database is off line';
        $pagetitle = 'Teknikal Tim - Database Error';
        $pagedescription = 'Teknikal Tim Database Error page';
        include_once 'dbdown.html.php';
        exit;
    }
    $headerinc = 'header.html.php';
}

public static function getInstance() {
    if(!isset(self::$_instance)) {
        self::$_instance = new DB();
    }

    return self::$_instance;

}


    public function query($sql, $params = array()) {
    $this->_error = false;
    if($this->_query = $this->_pdo->prepare($sql)) {
    $x = 1;
        if(count($params)) {
        foreach($params as $param){
            $this->_query->bindValue($x, $param);
            $x++;
            }
        }
    }
    if($this->_query->execute()) {

        $this->_results = $this->_query->fetchAll(PDO::FETCH_OBJ);
        $this->_count = $this->_query->rowCount();

    }

    else{
        $this->_error = true;
    }

    return $this;
}

public function action($action, $table, $where = array()) {
    if(count($where) ===3) {
        $operators = array('=', '>', '<', '>=', '<=');

        $field      = $where[0];
        $operator   = $where[1];
        $value      = $where[2];

        if(in_array($operator, $operators)) {
            $sql = "{$action} FROM {$table} WHERE {$field} = ?";

            if(!$this->query($sql, array($value))->error()) {
            return $this;
            }
        }

    }
    return false;
}

    public function get($table, $where) {
    return $this->action('SELECT *', $table, $where);

public function results() {
    return $this->_results;
}

public function first() {
    return $this->_results[0];
}

public function count() {
    return $this->_count;
}

}

to access the information I use this code on the controller script:

<?php
$pagetitle = 'Teknikal Tim - Service Call Reservation';
$pagedescription = 'Teknikal Tim Sevice Call Reservation Page';
require_once $_SERVER['DOCUMENT_ROOT'] .'/core/init.php';
$newsMessage = 'temp message';

$servicecallsdb = DB::getInstance()->get('tt_service_calls', array('UserID',
 '=','$_SESSION['UserID']));

if(!$servicecallsdb) {
// $servicecalls[] = array('ID'=>'','ServiceCallDescription'=>'No Service Calls');
} else {
$servicecalls = $servicecallsdb->results();
}
include 'servicecalls.html.php';



?>

then to display the information I check to see if servicecalls has been set and has a count greater than 0 remember it's not an array I am referencing so I access the records with the object operator "->" like this:

<?php include $_SERVER['DOCUMENT_ROOT'] .'/includes/header.html.php';?>
<!--Main content-->
<div id="mainholder"> <!-- div so that page footer can have a minum height from the
  header -->
<h1><?php if(isset($pagetitle)) htmlout($pagetitle);?></h1>
<br>
<br>
<article>
    <h2></h2>
</article>
<?php
if (isset($servicecalls)) {
if (count ($servicecalls) > 0){
     foreach ($servicecalls as $servicecall) {
        echo '<a href="/servicecalls/?servicecall=' .$servicecall->ID .'">'
  .$servicecall->ServiceCallDescription .'</a>';
    }
}else echo 'No service Calls';

}

?>
<a href="/servicecalls/?new=true">Raise New Service Call</a>
</div> <!-- Main content end-->
<?php include $_SERVER['DOCUMENT_ROOT'] .'/includes/footer.html.php'; ?>

Answer 16

改变它

$results->fetch_array()