How Can I Efficiently Instantiate Classes in PHP Using Strings?

Dynamic Class Instantiation with Strings

This question addresses the need to create class instances using strings in PHP, seeking a more efficient method than verbose switch statements.

Dynamic Class Instantiation

PHP provides a dynamic class instantiation feature that allows you to create an instance of a class using a string representing the class name. Here's how you do it:

$str = 'One';
$class = 'Class' . $str; // Concatenate the string with the class prefix
$object = new $class();

In this example, the dynamic class instantiation is based on the $str, which can have values of "One" or "Two." This is equivalent to writing:

if ($str == "One") {
    $object = new ClassOne();
} else if ($str == "Two") {
    $object = new ClassTwo();
}

Handling Namespaces

If your classes reside in namespaces, you can use a fully qualified name for the class:

$class = '\Foo\Bar\MyClass'; 
$instance = new $class();

Additional Dynamic Functionalities

Beyond class instantiation, PHP also supports dynamic function and method calls:

// Dynamic Function Call
$func = 'my_function';
$parameters = ['param2', 'param2'];
$func(...$parameters); // calls my_function() with 2 parameters

// Dynamic Method Call
$method = 'doStuff';
$object = new MyClass();
$object->$method(); // calls the MyClass->doStuff() method
// or in one call
(new MyClass())->$method();

Caution about Variable Variables

PHP allows the creation of variables named after strings, known as "variable variables." However, this is considered bad practice and should be avoided in favor of arrays.

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