PHP Array Exercises : Get the index of the highest value in an associative array

Last update on May 30 2022 11:45:34 (UTC/GMT +8 hours)

PHP Array: Exercise-31 with Solution

Write a PHP program to get the index of the highest value in an associative array.

Sample Solution:

PHP Code:

<?php
$x = array(
    'value1' => 3021,
    'value2' => 2365,
    'value3' => 5215,
    'value4' => 5214,
    'value5' => 2145);
reset($x);   // optional.
arsort($x);
$key_of_max = key($x);
echo "Index of the highest value : ".$key_of_max."\n";
?>

Sample Output:

Index of the highest value : value3

Flowchart:

PHP Code Editor:

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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