在关联数组中查找最后一对

Question

I'm looping through an associative array with a foreach. I'd like to be able to check if the key value pair being handled is the last so I can give it special treatment. Any ideas how I can do this the best way?

foreach ($kvarr as $key => $value){
   // I'd like to be able to check here if this key value pair is the last
   // so I can give it special treatment
}

Answer 1

Simple as this, free from counters and other 'hacks'.

foreach ($array as $key => $value) {

   // your stuff

   if (next($array) === false) {
      // this is the last iteration
   }
}

Please note that you have to use === , because the function next() may return a non-boolean value which evaluates to false , such as 0 or "" (empty string).

Answer 2

we don't need to iterate through the array with foreach, we can use the end(), key() and current() php functions to get to the last element and get it's key + value.

<?php

$a = Array(
  "fruit" => "apple",
  "car" => "camaro",
  "computer" => "commodore"
);

// --- go to the last element of the array & get the key + value --- 
end($a); 
$key = key($a);
$value = current($a);

echo "Last item: ".$key." => ".$value."\n";

?>

If you want to check it in the iteration, the end() function still can be useful:

foreach ($a as $key => $value) {
    if ($value == end($a)) {
      // this is the last element
    }
}

Answer 3

There are quite a few ways to do that as other answers will no doubt show. But I would suggest to learn SPL and its CachingIterator . Here is an example:

<?php

$array = array('first', 'second', 'third');

$object = new CachingIterator(new ArrayIterator($array));
foreach($object as $value) {
    print $value;

    if (!$object->hasNext()) {
        print "<-- that was the last one";
    }
}

It is more verbose than simple foreach, but not all that much. And all the different SPL iterators open up a whole new world for you, once you learn them :) Here is a nice tutorial.

Answer 4

Assuming you're not altering the array while iterating through it, you could maintain a counter that decrements in the loop and once it reaches 0, you're handling the last:

<?php
$counter = count($kvarr);
foreach ($kvarr as $key => $value)
{
    --$counter;
    if (!$counter)
    {
        // deal with the last element
    }
}
?>

Answer 5

You could use the array pointer traversal functions (specifically next ) to determine if there is another element after the current one:

$value = reset($kvarr);
do
{
  $key = key($kvarr);
  // Do stuff

  if (($value = next($kvarr)) === FALSE)
  {
    // There is no next element, so this is the last one.
  }
}
while ($value !== FALSE)

Note that this method won't work if your array contains elements whose value is FALSE , and you'll need to handle the last element after doing your usual loop body (because the array pointer is advanced by calling next ) or else memoize the value.