Title rewritten as: "The parameters of the foreach() function are invalid"

Question

It's common for me to deal with data that can be either an array or an empty variable, and feed that data to some foreach.

$values ​​= get_values();

foreach ($values ​​as $value){
  ...
}

When you provide foreach with data that is not an array, you will receive a warning:

Warning: Invalid argument supplied in foreach() in [...]

Assuming that the get_values() function cannot be refactored to always return an array (backward compatibility, unavailable source code, or any other reason), I would like to know how to avoid these warnings What is the cleanest and most efficient way:

• Convert $values to an array
• Initialize $values to an array
• Wrap foreach
in if
• Other (please provide suggestions)

Answer 1

how about this? It's more concise and it's all in one line.

foreach ((array) $items as $item) {
 // ...
 }

Answer 2

Personally, I think this is the cleanest - not sure if it's the most effective, mind you!

if (is_array($values) || is_object($values))
{
    foreach ($values as $value)
    {
        ...
    }
}

The reason for my preference is that it doesn't allocate an empty array when you don't have anything to begin with.