Question

Like iterrating a array, and using the index variable later instead of count() :

foreach($arr as $index => $val){
  ...

}

echo 'number of items: '.$index+1;

?

Answer 1

The language is explicitly OK with it.
I would not recommend it though, since it’s unusual to reuse loop-specific values outside the loop and you may introduce bugs if you refactor your loop some time later and forget the dependency a few lines down. In fact, it’s not a bad idea to explicitly unset($index, $val) after the loop to avoid such problems. This is especially true if you loop by reference (foreach ($foo as &$bar)).