PHP Exercises: Check a given array of integers, length 3 and create a new array

Last update on May 30 2022 11:40:50 (UTC/GMT +8 hours)

PHP Basic Algorithm: Exercise-98 with Solution

Write a PHP program to check a given array of integers, length 3 and create a new array. If there is a 5 in the given array immediately followed by a 7 then set 7 to 1.

Sample Solution:

PHP Code :

<?php
function test($numbers)
 { 
    for ($i = 0; $i < sizeof($numbers) - 1; $i++)
            {
                if ($numbers[$i] == 5 && $numbers[$i + 1] == 7)
                    $numbers[$i + 1] = 1;
            }
            return $numbers;
    
 }   

$a = [1, 5, 7];
echo "Original array: " . implode(',', $a) . "\n";
$result = test($a);
echo "New array with maximum values: " . implode(',', $result);

Sample Output:

Original array: 1,5,7
New array with maximum values: 1,5,1

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to check a given array of integers and return true if the array contains 10 or 20 twice. The length of the array will be 0, 1, or 2.
Next: Write a PHP program to compute the sum of the two given arrays of integers, length 3 and find the array which has the largest sum.

What is the difficulty level of this exercise?

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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