PHP array_multisort fails in PHP 8, works in PHP 7.4

✔ Recommended Answer

You seem to have the arrays backwards. The first array is what is actually sorted, and the second array has the same transformation applied to it.

array_multisort(    array_map(fn($page) => preg_replace('_^[^0-9a-z]*_', '', strtolower($page['title'])), $pages),    SORT_ASC, SORT_STRING,    $pages);

Source: stackoverflow.com

Answered By: Sammitch

Method #2

array_multisort has undergone some changes in PHP 8. One of the changes is that the function no longer accepts null values. If you try to pass a null value as one of the arguments, it will trigger a TypeError.

Here's an example of how to fix the issue:

php
// Example data
$data = [
    ['id' => 1, 'name' => 'John', 'age' => 30],
    ['id' => 2, 'name' => 'Mary', 'age' => 25],
    ['id' => 3, 'name' => 'Bob', 'age' => null],
];

// Create a separate array of ages to sort by
$ages = array_column($data, 'age');

// Replace null values with a placeholder value that can be sorted
foreach ($ages as $key => $value) {
    if ($value === null) {
        $ages[$key] = -1; // Replace with a negative number or any other placeholder value
    }
}

// Sort the data by age
array_multisort($ages, SORT_DESC, $data);

// Replace the placeholder value with null again
foreach ($ages as $key => $value) {
    if ($value === -1) {
        $data[$key]['age'] = null;
    }
}

// Print the sorted data
print_r($data);

In this example, we first create a separate array of ages to sort by using array_column(). Then, we replace any null values in the ages array with a placeholder value (in this case, -1). We sort the data using array_multisort(), and then replace the placeholder value with null again. Finally, we print the sorted data.

By replacing null values with a placeholder value before sorting, we can avoid triggering the TypeError in PHP 8.