PHP Class Properties
Description
Class properties are very similar to variables.
An object's property can store a single value, an array of values, or even another object.
Syntax
To add a property to a class, first write the keyword public, private, or protected, followed by the property's name preceded by a $symbol.
public, private, or protected are the visibility levels you want to give to the property:
class MyClass { /*from ww w. j a v a 2 s.co m*/
public $property1; // This is a public property
private $property2; // This is a private property
protected $property3; // This is a protected property
}
We can initialize properties at the time that we declare them:
class MyClass {
public $value = 123;
}
Accessing Properties
We can access the corresponding object's property value from within your calling code by using the following syntax:
$object->property;
Write the name of the variable storing the object, followed by an arrow symbol composed of a hyphen (-) and a greater - than symbol (>), followed by the property name.
Note that the property name doesn't have a $ symbol before it.
Example
We can add properties to a class.
<?PHP/*w w w . ja v a 2 s . com*/
class Shape{
public $Name;
public function say() {
print "shape";
}
}
$aRectangle = new Shape;
$aRectangle->say();
$aRectangle->Name = "Rect";
$aRectangle->say();
?>
The code above generates the following result.
-> is used to work with the property, and also that there is
no dollar sign before Name.
Each object has its own set of properties. Consider the following code:
<?PHP/*from www . ja v a2s. co m*/
class Shape{
public $Name;
public function say() {
print "shape";
}
}
class Rectangle extends Shape{
}
$aRect = new Rectangle;
$bRect = new Rectangle;
$aRect->Name = "A";
$bRect->Name = "B";
print $aRect->Name;
print $bRect->Name;
?>
PHP allows you to dynamically declare new properties for objects. It would create the property only for the object, and not for any other instances of the same class.