How to determine the first and last iteration in a foreach loop?

If you prefer a solution that does not require the initialization of the counter outside the loop, I propose comparing the current iteration key against the function that tells you the last / first key of the array.

This becomes somewhat more efficient (and more readable) with the upcoming PHP 7.3.

Solution for PHP 7.3 and up:

foreach($array as $key => $element) {
    if ($key === array_key_first($array))
        echo 'FIRST ELEMENT!';

    if ($key === array_key_last($array))
        echo 'LAST ELEMENT!';
}

Solution for all PHP versions:

foreach($array as $key => $element) {
    reset($array);
    if ($key === key($array))
        echo 'FIRST ELEMENT!';

    end($array);
    if ($key === key($array))
        echo 'LAST ELEMENT!';
}

You could use a counter:

$i = 0;
$len = count($array);
foreach ($array as $item) {
    if ($i == 0) {
        // first
    } else if ($i == $len - 1) {
        // last
    }
    // …
    $i++;
}

To find the last item, I find this piece of code works every time:

foreach( $items as $item ) {
    if( !next( $items ) ) {
        echo 'Last Item';
    }
}