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PHP Exercises: Create a new function that composes multiple functions into a single callable

PHP: Exercise-98 with Solution

Write a PHP program to create a new function that composes multiple functions into a single callable.

Sample Solution: -

PHP Code:

<?php
//Licence: https://bit.ly/2CFA5XY
function compose(...$functions)
{
    return array_reduce(
        $functions,
        function ($carry, $function) {
            return function ($x) use ($carry, $function) {
                return $function($carry($x));
            };
        },
        function ($x) {
            return $x;
        }
    );
}
$compose = compose(
    // add 2
    function ($x) {
        return $x + 2;
    },
    // multiply 4
    function ($x) {
        return $x * 4;
    }
);
print_r($compose(2));
echo("\n");
print_r($compose(3));

?>

Sample Output: 

16
20

Flowchart:

Flowchart: Create a new function that composes multiple functions into a single callable.

PHP Code Editor:

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Previous:Write a PHP program to decapitalize the first letter of the string and then adds it with rest of the string.
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PHP: Tips of the Day

Mutates the original array to filter out the values specified

Example:

<?php
function tips_pull(&$items, ...$params)
{
  $items = array_values(array_diff($items, $params));
  return $items;
}

$items = ['x', 'y', 'z', 'x', 'y', 'z'];
print_r(tips_pull($items, 'y', 'z'));
?>

Output:

Array
(
    [0] => x
    [1] => x
)