How to Sort an Array of Associative Arrays by a Column Value in PHP?

Sorting an Array of Associative Arrays by Column Value

Sorting data is a fundamental task in programming. When it comes to associative arrays, PHP provides several built-in functions to facilitate this process.

Consider the following array of associative arrays:

$inventory = array(
   array("type" => "fruit", "price" => 3.50),
   array("type" => "milk", "price" => 2.90),
   array("type" => "pork", "price" => 5.43)
);

The task is to sort the elements of $inventory by the "price" column in descending order, resulting in:

$inventory = array(
   array("type" => "pork", "price" => 5.43),
   array("type" => "fruit", "price" => 3.50),
   array("type" => "milk", "price" => 2.90)
);

Solution using array_multisort()

The array_multisort() function allows sorting an array (or multiple arrays) by multiple columns. To sort by "price" in descending order, the following code can be utilized:

$price = array();
foreach ($inventory as $key => $row) {
    $price[$key] = $row['price'];
}
array_multisort($price, SORT_DESC, $inventory);

Alternative Solution with array_column() (PHP 5.5.0 )

For PHP versions 5.5.0 and above, the array_column() function can be used to simplify the above code:

$price = array_column($inventory, 'price');
array_multisort($price, SORT_DESC, $inventory);

Usage

The sorted $inventory array can now be used as needed. For example, the following code would print the sorted array:

foreach ($inventory as $item) {
    echo $item['type'] . ": $" . $item['price'] . PHP_EOL;
}

Output:

pork: .43
fruit: .50
milk: .90

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