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Example analysis of STDCLASS usage in PHP

高洛峰
高洛峰Original
2016-12-21 14:31:411133browse

The example in this article describes the usage of STDCLASS in PHP. Share it with everyone for your reference, the details are as follows:

STDCLASS in PHP is not used much in our development applications, but STDCLASS in PHP is very useful. Let’s take a look at the usage of STDCLASS in PHP.

In many places in WordPress, stdClass is used to define an object (usually in the form of an array), and then get_object_vars is used to "convert" the defined object into an array.

The following code is shown:

$tanteng = new stdClass();
$tanteng->name = 'tanteng';
$tanteng->email = 'xxx@qq.com';
$info = get_object_vars($tanteng);
print_r($info);
exit;

Output:

Array ( [name] => tanteng [email] => xxx@qq.com )

The function of get_object_vars is to return an associative array composed of object attributes. Its effect is actually the same as defining an array like this:

$tanteng = array();
$tanteng['name'] = 'tanteng';
$tanteng['email'] = 'xxx@qq.com';

It can be understood like this: stdClass is a built-in class. It has no member variables or member methods. A new stdClass instantiates an "empty" class. 』Object, it is meaningless in itself, but what are the benefits of using stdClass to define it?

The following code:

$user = new stdClass();
$user->name = 'gouki';
$user->hehe = 'hehe';
$myUser = $user;
$myUser->name = 'flypig';
print_r($user);
print_r($myUser);
print_r($user);

Here $myUser is assigned the value $user, but in fact, there is no new memory storage variable, $myUser Still referring to the stdClass object, changing the property page of $myUser changes the properties of $user, instead of creating a new copy. If there are many such operations in the program, using stdClass can save memory overhead.

Running results:

stdClass Object
(
  [name] => flypig
  [hehe] => hehe
)
stdClass Object
(
  [name] => flypig
  [hehe] => hehe
)
stdClass Object
(
  [name] => flypig
  [hehe] => hehe
)

It can be seen from the results that changing the attributes of $myUser does change the stdClass attribute declared by $user. If $user is an array and is assigned to $myUser, then a copy is copied to $myUser. This increases System overhead.

Of course, you can also do the opposite and convert an array into an object:

$hehe['he1'] = 'he1';
$hehe['he2'] = 'he2';
$hh = (object) $hehe;
print_r($hh);

Print result:

stdClass Object ( [he1] => he1 [he2] => he2 )

I hope this article will be helpful to everyone in PHP programming.

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