PHP Exercises: Rotate the elements of a given array of integers in left direction and return the new array

Last update on May 30 2022 11:41:45 (UTC/GMT +8 hours)

PHP Basic Algorithm: Exercise-90 with Solution

Write a PHP program to rotate the elements of a given array of integers (length 4 ) in left direction and return the new array.

Sample Solution:

PHP Code :

<?php
function test($a1)
 { 
       return [$a1[1], $a1[2], $a1[3], $a1[0]];
    
 }   

$a = [10, 20, -30, -40];

echo "Original array: " . implode(',', $a) . "\n";

$result = test($a);

echo "Rotated array: " . implode(',', $result);

Sample Output:

Original array: 10,20,-30,-40
Rotated array: 20,-30,-40,10

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to compute the sum of the elements of an given array of integers.
Next: Write a PHP program to reverse a given array of integers and length 5.

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC