What is stdClass in PHP?

Question

Please define what stdClass is.

Answer 1

stdClass is PHP's generic empty class, kind of like Object in Java or object in Python (Edit: but not actually used as universal base class; thanks @Ciaran for pointing this out).

It is useful for anonymous objects, dynamic properties, etc.

An easy way to consider the StdClass is as an alternative to associative array. See this example below that shows how json_decode() allows to get an StdClass instance or an associative array. Also but not shown in this example, SoapClient::__soapCall returns an StdClass instance.

<?php
//Example with StdClass
$json = '{ "foo": "bar", "number": 42 }';
$stdInstance = json_decode($json);
echo $stdInstance->foo . PHP_EOL; //"bar"
echo $stdInstance->number . PHP_EOL; //42
//Example with associative array
$array = json_decode($json, true);
echo $array['foo'] . PHP_EOL; //"bar"
echo $array['number'] . PHP_EOL; //42

See Dynamic Properties in PHP and StdClass for more examples.

Answer 2

Also worth noting, an stdClass object can be created from the use of json_decode() as well.

Answer 3

Please bare in mind that 2 empty stdClasses are not strictly equal. This is very important when writing mockery expectations.

php > $a = new stdClass();
php > $b = new stdClass();
php > var_dump($a === $b);
bool(false)
php > var_dump($a == $b);
bool(true)
php > var_dump($a);
object(stdClass)#1 (0) {
}
php > var_dump($b);
object(stdClass)#2 (0) {
}
php >

Answer 4

php.net manual has a few solid explanation and examples contributed by users of what stdClass is, I especially like this one http://php.net/manual/en/language.oop5.basic.php#92123, https://stackoverflow.com/a/1434375/2352773.

stdClass is the default PHP object. stdClass has no properties, methods or parent. It does not support magic methods, and implements no interfaces.

When you cast a scalar or array as Object, you get an instance of stdClass. You can use stdClass whenever you need a generic object instance.

stdClass is NOT a base class! PHP classes do not automatically inherit from any class. All classes are standalone, unless they explicitly extend another class. PHP differs from many object-oriented languages in this respect.

You could define a class that extends stdClass, but you would get no benefit, as stdClass does nothing.

Answer 5

Likewise,

$myNewObj->setNewVar = 'newVal'; 

yields a stdClass object - auto casted

I found this out today by misspelling:

$GLOBASLS['myObj']->myPropertyObj->myProperty = 'myVal';

Cool!

Answer 6

Its also worth noting that by using Casting you do not actually need to create an object as in the answer given by @Bandula. Instead you can simply cast your array to an object and the stdClass is returned. For example:

$array = array(
    'Property1'=>'hello',
    'Property2'=>'world',
    'Property3'=>'again',
);

$obj = (object) $array;
echo $obj->Property3;

Output: again