What Does arsort Do?

arsort sorts an associative array in descending order based on its values, keeping the keys intact. A custom implementation requires:

1. Comparing array values.
2. Sorting values in descending order.
3. Maintaining the original key-value pair associations.

Custom Implementation of arsort in PHP

Below is a custom implementation of arsort using manual sorting logic:

<?php
function customArsort(&$array) {
    // Convert the associative array to an array of key-value pairs
    $keyValuePairs = [];
    foreach ($array as $key => $value) {
        $keyValuePairs[] = ["key" => $key, "value" => $value];
    }

    // Sort the array of pairs in descending order of values
    for ($i = 0; $i < count($keyValuePairs) - 1; $i++) {
        for ($j = 0; $j < count($keyValuePairs) - $i - 1; $j++) {
            if ($keyValuePairs[$j]["value"] < $keyValuePairs[$j + 1]["value"]) {
                $temp = $keyValuePairs[$j];
                $keyValuePairs[$j] = $keyValuePairs[$j + 1];
                $keyValuePairs[$j + 1] = $temp;
            }
        }
    }

    // Rebuild the original array with sorted values
    $array = [];
    foreach ($keyValuePairs as $pair) {
        $array[$pair["key"]] = $pair["value"];
    }
}

// Sample associative array
$data = [
    "apple" => 50,
    "banana" => 20,
    "cherry" => 80,
    "date" => 60,
];

// Apply custom arsort
customArsort($data);

// Output the sorted array
print_r($data);

Output:

Array
(
    [cherry] => 80
    [date] => 60
    [apple] => 50
    [banana] => 20
)

Benefits of Custom arsort

1. Full Control: Modify sorting logic for custom needs.
2. Flexibility: Add additional sorting criteria easily.
3. Learning Opportunity: Understand sorting algorithms and associative arrays.

Creating a custom arsort function in PHP provides valuable insights into sorting algorithms and array manipulation. While PHP’s built-in functions are powerful, a custom approach gives you complete control and a deeper understanding of how sorting works under the hood.

Keep Learning 🙂