How Can I Dynamically Call Functions and Methods in Programming?

Calling Functions Dynamically Using Variables

In programming, it's often useful to be able to call a function based on its name stored in a variable. This technique allows for greater flexibility and code reuse.

How to Call a Function from a Variable

To call a function from a variable, you can use one of the following methods:

1. Direct Function Call:

Assign the function name to a variable using single or double quotes (e.g., $functionName = "foo") and then call the function directly using the variable (e.g., $functionName()).

2. call_user_func():

The call_user_func() function takes a function name stored in a variable as its first argument and any necessary parameters as subsequent arguments.

Example:

function foo()
{
    // Code
}

function bar()
{
    // Code
}

$functionName = "foo";

// Call the function using direct function call
$functionName();

// Call the function using call_user_func()
call_user_func($functionName);

Passing Parameters from a Variable

To pass parameters stored in a variable array, use the array unpacking operator (...):

$function_name = 'trim';
$parameters = ['aaabbb', 'b'];
echo $function_name(...$parameters); // aaa

Creating Objects Dynamically and Calling Methods

To dynamically create an object and call its method, use the following syntax:

$class = 'DateTime';
$method = 'format';
echo (new $class)->$method('d-m-Y');

For static methods:

$class = 'DateTime';
$static = 'createFromFormat';
$date = $class::$static('d-m-Y', '17-08-2023');

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