How to Sort a PHP Array Based on a Custom Order?

Custom Order Array Sorting in PHP

Sorting arrays in PHP is typically done through comparison-based algorithms. However, there are situations where you need to sort arrays based on a predefined custom order.

Consider an array of arrays where each sub-array contains two keys: "id" and "title." You want to sort the main array in a specific order, such as:

[3452342, 5867867, 7867867, 1231233]

To achieve this, you can utilize the usort() function. This function allows you to specify a comparison function that defines how the array elements are compared.

In this case, the comparison function uses a closure to compare the positions of the "id" values in the custom order array ($order):

usort($array, function ($a, $b) use ($order) {
    $pos_a = array_search($a['id'], $order);
    $pos_b = array_search($b['id'], $order);
    return $pos_a - $pos_b;
});

The comparison function assigns the positions of the "id" values in the $order array to $pos_a and $pos_b. It then subtracts these positions to determine the order ($a comes before $b if $pos_a is less than $pos_b).

By using the custom order array and the comparison function, you can effectively sort your array of arrays in the predefined order.

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