How do I sort a multidimensional array by one of the fields of the inner array in PHP?

In PHP, you can sort a multidimensional array by one of the fields of the inner arrays using the usort() function with a custom comparison function, or using array_multisort() for simpler cases.

Using usort() with Custom Comparison Function

The usort() function sorts an array using a user-defined comparison function. This method provides the most flexibility for complex sorting logic ?

<?php
function compare_array($var_1, $var_2) {
    if ($var_1["price"] == $var_2["price"]) {
        return 0;
    }
    return ($var_1["price"] < $var_2["price"]) ? -1 : 1;
}

$my_Array = array(
    array("name" => "Product A", "price" => 25),
    array("name" => "Product B", "price" => 15),
    array("name" => "Product C", "price" => 35)
);

usort($my_Array, "compare_array");

foreach($my_Array as $item) {
    echo $item["name"] . " - $" . $item["price"] . "<br>";
}
?>

Product B - $15
Product A - $25
Product C - $35

Using array_multisort()

For simpler sorting by a single field, array_multisort() provides a more direct approach ?

<?php
$products = array(
    array("name" => "Product A", "price" => 25),
    array("name" => "Product B", "price" => 15),
    array("name" => "Product C", "price" => 35)
);

// Extract price column for sorting
$prices = array_column($products, 'price');

// Sort by price in ascending order
array_multisort($prices, SORT_ASC, $products);

foreach($products as $item) {
    echo $item["name"] . " - $" . $item["price"] . "<br>";
}
?>

Product B - 15
Product A - 25
Product C - 35

Sorting in Descending Order

To sort in descending order, modify the comparison function or use SORT_DESC ?

<?php
$products = array(
    array("name" => "Product A", "price" => 25),
    array("name" => "Product B", "price" => 15),
    array("name" => "Product C", "price" => 35)
);

$prices = array_column($products, 'price');
array_multisort($prices, SORT_DESC, $products);

foreach($products as $item) {
    echo $item["name"] . " - $" . $item["price"] . "<br>";
}
?>

Product C - 35
Product A - 25
Product B - 15

Conclusion

Use usort() for complex sorting logic and array_multisort() with array_column() for simple field-based sorting. Both methods effectively sort multidimensional arrays by specific fields.