PHP knowledge points

PHP knowledge points
1. Class Definition

  items[$artnr += $num;   }}

A class cannot be defined separately in multiple files, nor can the class be defined into multiple PHP blocks (internal functions can be divided ).
The following classes cannot be defined:
StdClass
_ Sleep
_ Wakeup
In fact, do not start with _ to define a class.

2. Constructor

class Cart {    var $todays_date;    var $name;    var $owner;    var $items = array(VCR, TV);    function Cart() {        $this->todays_date = date(Y-m-d);        $this->name = $GLOBALS['firstname'];        /* etc. . . */    }}

If the class has no constructor, the base class constructor is called.
The default value can be assigned to the constructor parameters.

  Add_item ($ item, $ num) ;}// buy the same boring old goods $ default_cart = new Constructor_Cart; // buy some real goods... $ different_cart = new Constructor_Cart (20, 17);?>

@ New can suppress errors in constructors.

3. Use of Classes

$cart = new Cart;$cart->add_item(10, 1);

Class uses $ this internally to represent itself.

4. class-related functions

_ Autoload-try to load undefined classes
Call_user_method_array-call a user method and pass the parameter array (obsolete)
Call_user_method-call the user Method for a specific object (obsolete)
Class_alias-create an alias for a class
Class_exists-check whether the class is defined
Get_called_class-name of the Static Binding ("Late Static Binding") Class
Get_class_methods-returns an array composed of class method names.
Get_class_vars-returns an array composed of the default attributes of the class.
Get_class-Class Name of the returned object
Get_declared_classes-returns an array composed of the names of defined classes.
Get_declared_interfaces-returns an array containing all declared interfaces.
Get_declared_traits-returns an array of all defined traits.
Get_object_vars-returns an associated array composed of object attributes.
Get_parent_class-return the parent class name of the object or Class
Interface_exists-check whether the interface has been defined
Is_a-if the object belongs to this class or the class is the parent class of this object, TRUE is returned.
Is_subclass_of-if this object is a subclass of this class, TRUE is returned.
Method_exists-check whether the class method exists
Property_exists-check whether the object or class has this attribute
Trait_exists-check whether the specified trait exists

5. Inheritance

  owner = $name;    }}?>

PHP does not support multi-inheritance.

6. Static Method

  ;}} Class B extends A {function example () {echo I am the redefined function B: example ().; a: example () ;}// Class A has no object, which will output // I am the original function A: example (). a: example (); // create A class B object $ B = new B; // This will output // I am the redefined function B: example (). // I am the original function A: example (). $ B-> example ();?>

7. base class references parent

  ;}} Class B extends A {function example () {echo I am B: example () and provide additional functionality .; parent: example () ;}}$ B = new B; // This will call B: example (), and it will call A: example (). $ B-> example ();?>

8. serialization

  One ;}}// page1.php: include (classa. inc); $ a = new A; $ s = serialize ($ a); // store $ s somewhere so that page2.php can find $ fp = fopen (store, w); fwrite ($ fp, $ s); fclose ($ fp); // page2.php: // This line of include (classa. inc); $ s = implode (, @ file (store); $ a = unserialize ($ s); // you can use show_one () of $ a object now () function $ a-> show_one ();?>

9. Magic function _ sleep _ wakeup10. method 1 of object attribute access in array Mode

Function obj2array (obj ){
Return new ArrayObject (obj, ArrayObject: ARRAY_AS_PROPS );
}
This method is relatively simple. It is more complicated to inherit ArrayAccess from another method.

11. Convert array to object

/*** Convert an array to an object ** @ param unknown $ e * @ return void | StdClass */public static function arrayToObject ($ e) {if (gettype ($ e )! = 'Array') return; foreach ($ e as $ k => $ v) {if (gettype ($ v) = 'array' | getType ($ v) = 'object') $ e [$ k] = (object) arrayToObject ($ v);} return (object) $ e ;}

12 self-implemented serialization and deserialization

Easy to use in redis:

/*** Serialized object, returns $ json string */public static function serialize ($ model) {// return serialize ($ model); if (! $ Model) return '{}'; $ json = '{'; foreach ($ model as $ key2 => $ value2) {if ($ json! = '{') $ Json. = ','; $ json. = $ key2: $ value2;} $ json. = '}'; return $ json;} public static function unserialize ($ json) {$ json = str_replace ('{', '', $ json ); $ json = str_replace ('}', '', $ json); $ array = explode (',', $ json); $ result = []; foreach ($ array as $ key => $ value) {$ temparr = explode (',', $ value); $ temparr1 = explode (':', $ temparr [0]); if (count ($ temparr1) = 0) continue; $ result [$ temparr1 [0] = trim ($ temparr1 [1], '');} // $ obj = (object) ($ result); return obj2array ($ result); // return $ result ;}