Can you provide an explanation of anonymous functions in PHP along with an illustrative example?

 Q. Can you provide an explanation of anonymous functions in PHP along with an illustrative example?
Answer:

    In PHP, an anonymous function, also known as a closure, is a function without a specified name. It's defined using the function keyword, followed by a set of parameters and a block of code. Anonymous functions are useful when you need to create a simple, one-time-use function, or when you want to pass a function as an argument to another function.

Here's the basic syntax of an anonymous function:
$anonymousFunction = function($param1, $param2) {
    // Function body
    return $param1 + $param2;
};

Here's a breakdown of the example:

$anonymousFunction: This variable now holds an anonymous function.
function($param1, $param2) { /* ... */ }: This is the definition of the anonymous function. It takes two parameters, $param1 and $param2, and the function body performs some operation (in this case, it returns the sum of the two parameters).
You can then call the anonymous function like this:
$result = $anonymousFunction(3, 4);
echo $result; // Output: 7

In this example, the anonymous function is called with arguments 3 and 4, and it returns 7.

Anonymous functions are often used in scenarios where you need to pass a function as an argument to another function, like in the array_map, array_filter, or usort functions. Here's an example using array_map:
$numbers = [1, 2, 3, 4, 5];

// Using an anonymous function to square each element in the array
$squaredNumbers = array_map(function($num) {
    return $num * $num;
}, $numbers);

print_r($squaredNumbers);
// Output: Array ( [0] => 1 [1] => 4 [2] => 9 [3] => 16 [4] => 25 )

In this example, the anonymous function squares each element in the $numbers array when used with array_map.

Another example:

<?php
$anonymousFunction = function($param1, $param2) {
    // Function body
    return $param1 + $param2;
};

// Invoke the function with specific arguments
$result = $anonymousFunction(3, 4);

// Echo the result
echo $result;
?>

 

Output: 7