What are the two types of objects in php?

Built-in objects: provided by PHP, do not depend on the host environment objects, these objects already exist before the program is executed. That is, built-in objects exist in any environment.

Custom objects: As the name suggests, they are objects defined by developers themselves. PHP allows the use of custom objects to expand PHP applications and functions

Object initialization (Recommended learning: PHP programming from entry to proficiency)

To create a new object object, use the new statement to instantiate a class:

<?php
class foo
{
    function do_foo()
    {
        echo "Doing foo."; 
    }
}

$bar = new foo;
$bar->do_foo();
?>

Convert to object

If you convert an object to an object, it will not change in any way. If a value of any other type is converted to an object, an instance of the built-in class stdClass will be created.

If the value is NULL, the new instance is empty. Converting array to object will make the key name a property name with corresponding value.

Note: In this example, using versions prior to PHP 7.2.0, the numeric keys can only be accessed via iteration.

<?php
$obj = (object) array(&#39;1&#39; => &#39;foo&#39;);
var_dump(isset($obj->{&#39;1&#39;})); // PHP 7.2.0 后输出 &#39;bool(true)&#39;，之前版本会输出 &#39;bool(false)&#39; 
var_dump(key($obj)); // PHP 7.2.0 后输出 &#39;string(1) "1"&#39;，之前版本输出  &#39;int(1)&#39; 
?>

For other values, the member variable name scalar will be included.

<?php
$obj = (object) &#39;ciao&#39;;
echo $obj->scalar;  // outputs &#39;ciao&#39;
?>

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