How can PHP developers improve their code structure to avoid nested loops and unnecessary function calls for better efficiency?

To improve code structure and efficiency in PHP, developers can avoid nested loops and unnecessary function calls by refactoring their code to use more efficient algorithms and data structures. One way to achieve this is by breaking down complex logic into smaller, more manageable functions and using built-in PHP functions where possible.

// Example of refactoring code to avoid nested loops and unnecessary function calls
function calculateSum(array $numbers) {
    $sum = 0;
    
    foreach ($numbers as $number) {
        $sum += $number;
    }
    
    return $sum;
}

$numbers = [1, 2, 3, 4, 5];
$totalSum = calculateSum($numbers);
echo $totalSum;