Question

How to use an anonymous function in PHP

Answer 1

// Anonymous function = A function with no identifier.

$greet = function($name) {
    echo "Hello $name\n";
};

$greet("World");
$greet("PHP");


/*
run:

Hello World
Hello PHP

*/

 

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Answer 2

// Anonymous function = A function with no identifier.
// Using an anonymous function as a callback

$numbers = [1, 2, 3, 4, 5];

$squared = array_map(function($n) {
    return $n * $n;
}, $numbers);

print_r($squared);



/*
run:

Array
(
    [0] => 1
    [1] => 4
    [2] => 9
    [3] => 16
    [4] => 25
)

*/

 

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Answer 3

// Anonymous function = A function with no identifier.
// Anonymous functions can inherit variables from the parent scope using use

$multiplier = 2;

$double = function($n) use ($multiplier) {
    return $n * $multiplier;
};

echo $double(5); 



/*
run:

10

*/

 

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Answer 4

// Anonymous function = A function with no identifier.
// Immediately‑invoked anonymous function (IIFE)
// define and execute an anonymous function in one step. 

(function() {
    echo "Runs immediately!";
})();



/*
run:

Runs immediately!

*/

 

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