如何在foreach循环中获取当前数组索引？

Question

How do I get the current index in a foreach loop?

foreach ($arr as $key => $val)
{
    // How do I get the index?
    // How do I get the first element in an associative array?
}

Answer 1

In your sample code, it would just be $key.

If you want to know, for example, if this is the first, second, or i^th iteration of the loop, this is your only option:

$i = -1;
foreach($arr as $val) {
  $i++;
  //$i is now the index.  if $i == 0, then this is the first element.
  ...
}

Of course, this doesn't mean that $val == $arr[$i] because the array could be an associative array.