How can I get the current array index in a foreach loop?

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.

This is the most exhaustive answer so far and gets rid of the need for a $i variable floating around. It is a combo of Kip and Gnarf's answers.

$array = array( 'cat' => 'meow', 'dog' => 'woof', 'cow' => 'moo', 'computer' => 'beep' );
foreach( array_keys( $array ) as $index=>$key ) {

    // display the current index + key + value
    echo $index . ':' . $key . $array[$key];

    // first index
    if ( $index == 0 ) {
        echo ' -- This is the first element in the associative array';
    }

    // last index
    if ( $index == count( $array ) - 1 ) {
        echo ' -- This is the last element in the associative array';
    }
    echo '<br>';
}

Hope it helps someone.

foreach($array as $key=>$value) {
    // do stuff
}

$key is the index of each $array element

$i = 0;
foreach ($arr as $key => $val) {
  if ($i === 0) {
    // first index
  }
  // current index is $i

  $i++;
}