Usage analysis of stdClass in php, phpstdclass usage_PHP tutorial

Usage analysis of stdClass in php, phpstdclass usage

This article analyzes the usage of stdClass in php with examples. Share it with everyone for your reference. The specific analysis is as follows:

stdclass is one of several predefined classes in php and is a class reserved by zent. In fact, it is a base class provided by PHP, which is a blank class with nothing in it. We can instantiate it, then define a series of variables, and pass variables through it (many PHP programmers use it to Pass the values ​​of a series of variables while not bothering to create a class of your own). However, since methods cannot be added after instantiation, only properties can be passed. Because once a class is instantiated, methods cannot be added.

stdclass can be used as a base class. Its biggest feature is that (its derived classes) can automatically add member variables without the need to specify them when defining.

All php variables are instances of stdClass.

How to use:

1. Use stdclass:

$andy = array();
$andy = (object)$andy;
$andy->a = 1;
$andy->b = 2;
$andy->c = 3;

In this way, the quantities a, b, and c are filled in stdclass. This saves trouble, because to create an empty object requires $andy = new Andy; and there must be a class Andy{} first. Another example:

<?php
$a = new stdClass();
$a->id = '11 ';
$a->username = 'me';
print_r($a);
?>

Will output: stdClass Object ( [id] => 11 [username] => me ).
Many times, this method is used to replace the use of arrays, which is just a different syntax.

2. Read:

stdClass Object
(
  [getWeatherbyCityNameResult] => stdClass Object
    (
      [string] => Array
        (
          [0] => 四川
          [1] => 成都
          [2] => 56294
          [3] => 56294.jpg
          [4] => 2009-5-17 13:52:08
          [5] => 26℃/19℃
          [6] => 5月17日 阴转阵雨
        )
    )
)

In fact, it is similar to array, but the access method changes a little. We are generally accustomed to using array['key'] to access arrays.
For this kind of stdClass, as in the above example, $weather->getWeatherbyCityNameResult->string[0] can access the attribute like this, and the result will be "Sichuan".

3. Instantiation, new.

Compare these two codes:

<?php  
$a = array(1=>2,2=>3);
$a = (object)$a;
$a->id = '11 ';
$a->username = 'me';
print_r($a);
?>

Will output: stdClass Object ( [1] => 2 [2] => 3 [id] => 11 [username] => me ) .

<?php  
$a = array(1=>2,2=>3);
$a = (object)$a;
$a = new stdClass();
$a->id = '11 ';
$a->username = 'me';
print_r($a);
?>

Will output: stdClass Object ( [id] => 11 [username] => me ) .

It turns out that after instantiating with new, the previous array is cleared, leaving only the ones added later. If not instantiated, stdClass will retain all elements.

It should be noted that when using global or static in a function and new stdclass is referenced, &new stdclass will be invalid. You should avoid using references and use new stdclass directly.

I hope this article will be helpful to everyone’s PHP programming design.

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