PHP Super Global variables, magic variables and Magic methods

PHP has been designed with 9 super-global variables, 8 magic variables, and 13 magic methods, which can be used anywhere in the script without a declaration. These variables and functions are frequently used in PHP development, and these variables and functions can easily help us solve many problems. The following is a detailed explanation of the hyper-global variables, magic variables, and Magic methods in PHP.

PHP Super Global Variables (9)

$GLOBALS store variables in the global scope

$_server Getting server-related information

$_request getting the parameters for post and get requests

$_post get the form's POST request parameters

$_get GET request parameters for a form

$_files get the variable to upload the file

$_env getting an array of server-side environment variables

$_cookie Browser COOKIE operation

Set Cookie:setcookie (name, value, expire, path, domain);

Get cookie:$_cookie["user"];

Delete Cookie:setcookie ("User", "", Time ()-3600);//Set Expiration

Operation of $_session server SESSION

Be sure to Session_Start () Start session before using the session

Storage session:$_session["name"]= "King";//Array operation

Destroy Session:unset ($_session["name"]);//Destroy A

Session_destroy () and unset ($_session);//Destroy All SESSION

PHP Magic variables (8)

The current line number in the __line__ file.

The full path and file name of the __file__ file. If used in the included file, returns the file name that is included.

The directory where the __dir__ file resides. If used in the included file, returns the directory where the included files are located.

The __FUNCTION__ constant returns the name of the function when it is defined

The __CLASS__ constant returns the name of the class when it is defined (case-sensitive).

__trait__ TRAIT's name (PHP 5.4.0 new addition). Since PHP 5.4.0, PHP has implemented a method of code reuse, called traits.

The method name of the __method__ class (PHP 5.0.0 new addition). Returns the name of the method when it is defined (case-sensitive).

__NAMESPACE__ the name of the current namespace (case sensitive). This constant is defined at compile time (PHP 5.3.0 is new).

PHP Magic Method (13)

__construct () is called when an object is instantiated, and when __construct and a function with a class name are present, __construct is called and the other is not called.

__destruct () is called when an object is deleted or when an object operation terminates.

The __call () object invokes a method that is called directly if the method exists, or calls the __call function if it does not exist.

__get () When the property of an object is read, the property value is returned directly if it exists, and the __get function is called if it does not exist.

__set () Sets the property of an object, assigns the value directly if the attribute exists, or calls the __set function if it does not exist.

__tostring () is called when an object is printed. such as Echo $obj; or print $obj;

__clone () is called when the object is cloned. such as: $t =new Test (); $t 1=clone $t;

__sleep () serialize was called before. If the object is relatively large, want to cut a bit of the east and then serialize, you can consider this function.

__wakeup () Unserialize is called to do some initialization of the object.

__isset () is called when detecting whether an object's properties exist. such as: Isset ($c->name).

__unset () is called when a property of an object is unset. such as: unset ($c->name).

Called when the __set_state () call is Var_export. Use the return value of __set_state as the return value of Var_export.

__autoload () When an object is instantiated, the method is called if the corresponding class does not exist.

