PHP Exercises: Create a new array of given length using the odd numbers from a given array of positive integers

Last update on May 30 2022 11:40:58 (UTC/GMT +8 hours)

PHP Basic Algorithm: Exercise-136 with Solution

Write a PHP program to create a new array of given length using the odd numbers from a given array of positive integers.

Sample Solution:

PHP Code :

<?php
function test($nums, $count)
    { 
      $evens = [$count];
        $j = 0;

        for ($i = 0; $j < $count; $i++)
            {
                if ($nums[$i] % 2 != 0)
                {
                    $evens[$j] = $nums[$i];
                    $j++;
                }
            }

            return $evens;
    }
    
$result = test([1,2,3,5,7,9,10], 3);
echo "New array: ".implode(",", $result);

Sample Output:

New array: 1,3,5

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to check a positive integer and return true if it contains a number 2.

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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