Get next element in foreach loop

As php.net/foreach points out:

Unless the array is referenced, foreach operates on a copy of the specified array and not the array itself. foreach has some side effects on the array pointer. Don't rely on the array pointer during or after the foreach without resetting it.

In other words - it's not a very good idea to do what you're asking to do. Perhaps it would be a good idea to talk with someone about why you're trying to do this, see if there's a better solution? Feel free to ask us in ##PHP on irc.freenode.net if you don't have any other resources available.

A unique approach would be to reverse the array and then loop. This will work for non-numerically indexed arrays as well:

$items = array(
    'one'   => 'two',
    'two'   => 'two',
    'three' => 'three'
);
$backwards = array_reverse($items);
$last_item = NULL;

foreach ($backwards as $current_item) {
    if ($last_item === $current_item) {
        // they match
    }
    $last_item = $current_item;
}

If you are still interested in using the current and next functions, you could do this:

$items = array('two', 'two', 'three');
$length = count($items);
for($i = 0; $i < $length - 1; ++$i) {
    if (current($items) === next($items)) {
        // they match
    }
}

#2 is probably the best solution. Note, $i < $length - 1; will stop the loop after comparing the last two items in the array. I put this in the loop to be explicit with the example. You should probably just calculate $length = count($items) - 1;

If the indexes are continuous:

foreach ($arr as $key => $val) {
   if (isset($arr[$key+1])) {
      echo $arr[$key+1]; // next element
   } else {
     // end of array reached
   }
}

You could probably use while loop instead of foreach:

while ($current = current($array) )
{
    $next = next($array);
    if (false !== $next && $next == $current)
    {
        //do something with $current
    }
}