How to sort an array of associative arrays by value of a given key in

// Example array of associative arrays
$users = array(
    array('name' => 'John', 'age' => 25),
    array('name' => 'Alice', 'age' => 30),
    array('name' => 'Bob', 'age' => 20)
);

// Function to compare two arrays by the value of the 'age' key
function compareByAge($a, $b) {
    if ($a['age'] == $b['age']) {
        return 0;
    }
    return ($a['age'] < $b['age']) ? -1 : 1;
}

// Sort the array by the 'age' key
usort($users, 'compareByAge');

// Print the sorted array
print_r($users);