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PHP Exercises: Call a given function only once

PHP: Exercise-101 with Solution

Write a PHP program to call a given function only once.

Sample Solution: -

PHP Code:

<?php
//Licence: https://bit.ly/2CFA5XY

function once($function)
{
    return function (...$args) use ($function) {
        static $called = false;
        if ($called) {
            return;
        }
        $called = true;
        return $function(...$args);
    };
}

$add = function ($a, $b) {
    return $a + $b;
};

$once = once($add);

var_dump($once(10, 5));  
var_dump($once(20, 10));
  
?>

Sample Output: 

int(15)
NULL

Flowchart:

Flowchart: Call a given function only once.

PHP Code Editor:

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Previous:Write a PHP program to curry a function to take arguments in multiple calls.
Next: Write a PHP program to capture a variable number of arguments to a given function.

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PHP: Tips of the Day

Returns all elements in an array except for the first one

Example:

<?php
function tips_tail($items)
{
  return count($items) > 1 ? array_slice($items, 1) : $items;
}

print_r(tips_tail([1, 5, 7]));
?>

Output:

Array
(
    [0] => 5
    [1] => 7
)