Understanding Static Variables in PHP

In the world of PHP programming, static variables are one of the important features that allow you to access these variables without needing to create an instance of the class, as well as sometimes accessing them directly.

Using static variables makes sense when they perform operations that are more general in nature and do not require a specific condition. For instance, a function that performs auxiliary tasks can be defined as static.

To define a variable as static in PHP, it is sufficient to use the key word static. This feature allows you to use this variable without creating one, and also provides the advantage of usage in high-performance projects and many requests.

Another benefit of using static variables is that your code tends to find a higher prevalence of finding in the libraries that may exclusively be implemented with static variables for performing similar tasks. This style of coding is particularly prevalent in frameworks and packages.

Additionally, keep in mind that in classes that require inheritance and contain static variables, using the key word self is necessary to refer to these variables, which will always be inherited from the base class. In cases where you intend to have them in descendant classes, you can use static::.

In continuation, we will provide examples of how to define and use static variables in PHP.

<?php
class MathHelper {
    public static function add($a, $b) {
        return $a + $b;
    }

    public static function multiply($a, $b) {
        return $a * $b;
    }
}

// Using static methods
echo MathHelper::add(5, 10); // Output: 15
echo MathHelper::multiply(3, 4); // Output: 12
?>

Line-by-Line Explanations

<?php
This code indicates the start of a PHP file.

class MathHelper {
Defines a class named MathHelper.

public static function add($a, $b) {
Defines a static method that adds two values.

return $a + $b;
Returns the result of adding $a and $b.

public static function multiply($a, $b) {
Defines another static method that multiplies two values.

return $a * $b;
Returns the result of multiplying $a and $b.

}
The closing of the definition of one of the methods.

echo MathHelper::add(5, 10);
Calls the static method add and prints its result.

echo MathHelper::multiply(3, 4);
Calls the static method multiply and prints its result.