PHP Exercises: Count even number of elements in a given array of integers

Last update on May 30 2022 11:41:46 (UTC/GMT +8 hours)

PHP Basic Algorithm: Exercise-106 with Solution

Write a PHP program to count even number of elements in a given array of integers.

Sample Solution:

PHP Code :

<?php
function test($nums)
 { 

     $evens = 0;
 
     for ($i = 0; $i < sizeof($nums); $i++)
          {
            if ($nums[$i] % 2 == 0) $evens++;
          }
      return $evens;
 }   

echo "Number of even elements: ". test([1, 5, 7, 9, 10, 12] );

Sample Output:

Number of even elements: 2

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to create a new array taking the first two elements from a given array. If the length of the given array is less than 2 then return the give array.
Next: Write a PHP program to compute the difference between the largest and smallest values in a given array of integers and length one or more.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

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