Question

Having the reference in the foreach, what does it mean and what the benefit?

For example:

foreach ($delivery as &$store) {
            $store = ClassName::FunctionName($store);
} 
unset($store);

I never really use reference when I do some coding in PHP.

Answer 1

If you don’t pass by reference into the foreach loop, any changes and updates won’t automatically be retained in the initial data structure after the loop has completed.

For example:

$test = array('cat'=>'meow','dog'=>'woof');

foreach($test as $a){
    $a='test';
}
print_r($test);

In this case, the array will still contain:

array('cat'=>'meow','dog'=>'woof');

However in this example using references:

$test=array('cat'=>'meow','dog'=>'woof');

foreach($test as &$a){
    $a='test';
}
var_dump($test);

…the array will contain:

array('cat'=>'test','dog'=>'test');