PHP OOP - Static Properties
PHP - Static Properties
Static properties can be called directly - without creating an instance of a class.
Static properties are declared with the static keyword:
Syntax
<?php
class ClassName {
public static $staticProp = "W3Schools";
}
?>
To access a static property use the class name, double colon (::), and the property name:
Syntax
ClassName::$staticProp;
Let's look at an example:
Example
<?php
class pi {
public static $value = 3.14159;
}
// Get static property
echo pi::$value;
?>
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Example Explained
Here, we declare a static property: $value. Then, we echo the value of the static property by using the class name, double colon (::), and the property name (without creating a class first).
PHP - More on Static Properties
A class can have both static and non-static properties. A static property can be accessed from a method in the same class using the self keyword and double colon (::):
Example
<?php
class pi {
public static $value=3.14159;
public function staticValue() {
return self::$value;
}
}
$pi = new pi();
echo $pi->staticValue();
?>
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To call a static property from a child class, use the parent keyword inside the child class:
Example
<?php
class pi {
public static $value=3.14159;
}
class x extends pi {
public function xStatic() {
return parent::$value;
}
}
// Get value of static property directly via child class
echo x::$value;
// or get value of static property via xStatic() method
$x = new x();
echo $x->xStatic();
?>
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