PHP: What is More Powerful Than list()

First of all list() is not an unknown method in the PHP community, where almost every PHP developer knows what it does. The pity is that it has, perhaps, remained useless, although there is hidden power in it!

What is list()?

Let’s assume you’ve two variables and one array with two elements:

$arr = array(1, 2);
$a = $arr[0];
$b = $arr[1];
// now a == 1, and b == 2

Maybe the easiest way to assign to the first variable the value of the first element of the array, and to the second variable the value of the second element of the array is to use list():

list($a, $b) = array(1, 2);
// again a == 1, and b == 2

Note that you can do the same with as many variables/array elements you want.

The funny thing is that nobody use it, while I see at least one perfect usage. You can think of a typical admin panel of any web system. For sure any developer has programmed the typical table page containing a list of “things” and a paging to switch the result set page. It’s like the posts page from the WordPress admin panel, or a search result page in Google, where you’ve one page of results and at the bottom – a number of pages where you can go to another page of the search results.

What I’ve seen in almost every project is that typically the developers prefer to set the results for the page into one list returned from one method and the count of the entire result set is returned by another method.

Thus most of the times there are two methods, performing most commonly a database queries. Something like – getList($offset, $limit) and getCount() where the first one returns the page and the second one returns the count of the result set.

This will result into two methods, two calls and two lines of code:

function getList($offset, $limit)
	// although the entire result set contains
	// 5 elements by limiting it from the parameters
	// only three are returned
	return $list; // where $list = array('title1', 'title2', 'title3');	
function getCount()
	// here's returned the count
	// of the entire result set
	return $count; // where $count = 5;	
$list  = getList(0, 3);
$count = getCount();

What actually you can do is to perform both queries in one method, perhaps called getItems($offset, $limit) where the returned value is an array containing both the list of results and the count:

function getItems($offset, $limit)
	return array('list' => $list, 'count' => $count);

And finally when calling this method to list() that into the two variables – single lined.

list($list, $count) = getItems(0, 3);

6 thoughts on “PHP: What is More Powerful Than list()

  1. This seems like a good use of the list() function! My only questions is how are you gonna fetch just the amount of records (for example when displaying: “There are 465 comments on this blog”) without actually fetching all the results?

  2. Actually this is a pretty good question! Well than this will fetch all the results only to return the count – which is stupid. Than you’ve to have two methods – one for the list and another for the count. What happens often in my practice is that in many cases I need both the list and the count, while only for few sets I need a separate count method. It all depends of the use case, of course.

  3. There’s one problem to this though, list() takes only numerical arrays and not associative arrays. If you return an associative array then list won’t assign anything.

    But then again, returning numerical arrays aren’t as.. maintainable as returning associative arrays.

    Maybe you should just return associative arrays or maybe objects.

  4. There’s always pass-by-reference – that’s the traditional C-way to do things, anyway.

    function getData($id, &$records, &$count) {...}

    Disadvantage: Pass-by-reference isn’t clear in the calling code

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