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 $obj = (object) array('1' => 'foo'); var_dump(isset($obj->{'1'})); // PHP 7.2.0 后输出 'bool(true)',之前版本会输出 'bool(false)' var_dump(key($obj)); // PHP 7.2.0 后输出 'string(1) "1"',之前版本输出 'int(1)' ?>
For other values, the member variable name scalar will be included.
<?php $obj = (object) 'ciao'; echo $obj->scalar; // outputs 'ciao' ?>
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