What are some best practices for iterating through multidimensional arrays in PHP to avoid memory issues or performance problems?

When iterating through multidimensional arrays in PHP, it's important to use efficient methods to avoid memory issues and performance problems. One common approach is to use nested loops to traverse the array elements. Another method is to use recursive functions for deep traversal. Additionally, consider using array functions like array_walk_recursive() or array_map() for more complex operations.

// Example of iterating through a multidimensional array using nested loops
$multiArray = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
];

foreach ($multiArray as $innerArray) {
    foreach ($innerArray as $value) {
        echo $value . " ";
    }
}