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name Punditsdkoslkdosdkoskdo

Smart pagination algorithm [closed]

I had the same need a while ago.

Here's the article I used to get it done (with PHP code): Digg-Style Pagination

It works pretty fast and has some additions to what you're trying to do, like:

[1] 2 3 4 5 6 ... 100
1 [2] 3 4 5 6 ... 100
...
1 ... 4 5 [6] 7 8 ... 100

Here is the code from the broken link:

<?php
    /*
        Place code to connect to your DB here.
    */

    // How many adjacent pages should be shown on each side?
    $adjacents = 3;

    /* 
       First get total number of rows in data table. 
       If you have a WHERE clause in your query, make sure you mirror it here.
    */
    $query = "SELECT COUNT(*) as num FROM portfolio";
    $total_pages = mysql_fetch_array(mysql_query($query));
    $total_pages = $total_pages[num];

    /* Setup vars for query. */
    $limit = 2;                                 //how many items to show per page
    if($page) 
        $start = ($page - 1) * $limit;          //first item to display on this page
    else
        $start = 0;                             //if no page var is given, set start to 0

    /* Get data. */
    $query = "SELECT category, uname, title FROM portfolio LIMIT $start, $limit";
    $portfolio = mysql_query($query);

    /* Setup page vars for display. */
    if ($page == 0) $page = 1;                  //if no page var is given, default to 1.
    $prev = $page - 1;                          //previous page is page - 1
    $next = $page + 1;                          //next page is page + 1
    $lastpage = ceil($total_pages/$limit);      //lastpage is = total pages / items per page, rounded up.
    $lpm1 = $lastpage - 1;                      //last page minus 1

    /* 
        Now we apply our rules and draw the pagination object. 
        We're actually saving the code to a variable in case we want to draw it more than once.
    */
    $pagination = "";
    if($lastpage > 1)
    {   
        $pagination .= "<div class="\"pagination\"">";
        //previous button
        if ($page > 1) 
            $pagination.= "<a href="\"diggstyle.php?page=$prev\"">« previous</a>";
        else
            $pagination.= "<span class="\"disabled\"">« previous</span>";   

        //pages 
        if ($lastpage < 7 + ($adjacents * 2))   //not enough pages to bother breaking it up
        {   
            for ($counter = 1; $counter <= $lastpage; $counter++)
            {
                if ($counter == $page)
                    $pagination.= "<span class="\"current\"">$counter</span>";
                else
                    $pagination.= "<a href="\"diggstyle.php?page=$counter\"">$counter</a>";                 
            }
        }
        elseif($lastpage > 5 + ($adjacents * 2))    //enough pages to hide some
        {
            //close to beginning; only hide later pages
            if($page < 1 + ($adjacents * 2))        
            {
                for ($counter = 1; $counter < 4 + ($adjacents * 2); $counter++)
                {
                    if ($counter == $page)
                        $pagination.= "<span class="\"current\"">$counter</span>";
                    else
                        $pagination.= "<a href="\"diggstyle.php?page=$counter\"">$counter</a>";                 
                }
                $pagination.= "...";
                $pagination.= "<a href="\"diggstyle.php?page=$lpm1\"">$lpm1</a>";
                $pagination.= "<a href="\"diggstyle.php?page=$lastpage\"">$lastpage</a>";       
            }
            //in middle; hide some front and some back
            elseif($lastpage - ($adjacents * 2) > $page && $page > ($adjacents * 2))
            {
                $pagination.= "<a href="\"diggstyle.php?page=1\"">1</a>";
                $pagination.= "<a href="\"diggstyle.php?page=2\"">2</a>";
                $pagination.= "...";
                for ($counter = $page - $adjacents; $counter <= $page + $adjacents; $counter++)
                {
                    if ($counter == $page)
                        $pagination.= "<span class="\"current\"">$counter</span>";
                    else
                        $pagination.= "<a href="\"diggstyle.php?page=$counter\"">$counter</a>";                 
                }
                $pagination.= "...";
                $pagination.= "<a href="\"diggstyle.php?page=$lpm1\"">$lpm1</a>";
                $pagination.= "<a href="\"diggstyle.php?page=$lastpage\"">$lastpage</a>";       
            }
            //close to end; only hide early pages
            else
            {
                $pagination.= "<a href="\"diggstyle.php?page=1\"">1</a>";
                $pagination.= "<a href="\"diggstyle.php?page=2\"">2</a>";
                $pagination.= "...";
                for ($counter = $lastpage - (2 + ($adjacents * 2)); $counter <= $lastpage; $counter++)
                {
                    if ($counter == $page)
                        $pagination.= "<span class="\"current\"">$counter</span>";
                    else
                        $pagination.= "<a href="\"diggstyle.php?page=$counter\"">$counter</a>";                 
                }
            }
        }

        //next button
        if ($page < $counter - 1) 
            $pagination.= "<a href="\"diggstyle.php?page=$next\"">next »</a>";
        else
            $pagination.= "<span class="\"disabled\"">next »</span>";
        $pagination.= "</div>\n";       
    }
?>
<ul>
    <?php
        while($item = mysql_fetch_array($portfolio))
        {
    ?>
        <li><a href="/web/20080709045706/http://www.strangerstudios.com/portfolio//"></a></li>
    <?php
        }
    ?>
</ul>
<?=$pagination?>
  • 32
Reply Report

Kinda late =), but here is my go at it:

function Pagination($data, $limit = null, $current = null, $adjacents = null)
{
    $result = array();

    if (isset($data, $limit) === true)
    {
        $result = range(1, ceil($data / $limit));

        if (isset($current, $adjacents) === true)
        {
            if (($adjacents = floor($adjacents / 2) * 2 + 1) >= 1)
            {
                $result = array_slice($result, max(0, min(count($result) - $adjacents, intval($current) - ceil($adjacents / 2))), $adjacents);
            }
        }
    }

    return $result;
}

Example:

$total = 1024;
$per_page = 10;
$current_page = 2;
$adjacent_links = 4;

print_r(Pagination($total, $per_page, $current_page, $adjacent_links));

Output (@ Codepad):

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
)

Another example:

$total = 1024;
$per_page = 10;
$current_page = 42;
$adjacent_links = 4;

print_r(Pagination($total, $per_page, $current_page, $adjacent_links));

Output (@ Codepad):

Array
(
    [0] => 40
    [1] => 41
    [2] => 42
    [3] => 43
    [4] => 44
)
  • 15
Reply Report
      • 1
    • its works all good except $result = range(1, intval($data / $limit)); instead of $result = range(1, ceil($data / $limit)); ceil is creating one extra page
    • @JapanPro: And it should? If you have 99 results and you want to display 10 per page, you'll need ceil(99 / 10) = 10 pages.
      • 1
    • @Alix Axel Nice answer!! but a better implementation would have been creating the array at the end instead of slicing a pre-existing one.... (e.g. what if you have 12k pages)

I started from the lazaro's post and tried to make a robust and light algorithm with javascript/jquery... No additional and/or bulky pagination libraries needed... Look on fiddle for an live example: http://jsfiddle.net/97JtZ/1/

var totalPages = 50, buttons = 5;
var currentPage = lowerLimit = upperLimit = Math.min(9, totalPages);

//Search boundaries
for (var b = 1; b < buttons && b < totalPages;) {
    if (lowerLimit > 1 ) { lowerLimit--; b++; }
    if (b < buttons && upperLimit < totalPages) { upperLimit++; b++; }
}

//Do output to a html element
for (var i = lowerLimit; i <= upperLimit; i++) {
    if (i == currentPage) $('#pager').append('<li>' + i + '</li> ');
    else $('#pager').append('<a href="#"><li><em>' + i + '</em></li></a> ');
}
  • 9
Reply Report
List<int> pages = new List<int>();
int pn = 2; //example of actual pagenumber
int total = 8;

for(int i = pn - 9; i <= pn + 9; i++)
{
  if(i < 1) continue;
  if(i > total) break;
  pages.Add(i);
}

return pages;
  • 3
Reply Report

I made a pagination class and put in on Google Code a while ago. Check it out its pretty simple http://code.google.com/p/spaceshipcollaborative/wiki/PHPagination

$paging = new Pagination();
$paging->set('urlscheme','class.pagination.php?page=%page%');
$paging->set('perpage',10);
$paging->set('page',15);
$paging->set('total',3000);
$paging->set('nexttext','Next Page');
$paging->set('prevtext','Previous Page');
$paging->set('focusedclass','selected');
$paging->set('delimiter','');
$paging->set('numlinks',9);
$paging->display();
  • 2
Reply Report

I would use something simple on the page you are showing the paginator, like:

if (
  $page_number == 1 || $page_number == $last_page ||
  $page_number == $actual_page ||
  $page_number == $actual_page+1 || $page_number == $actual_page+2 ||
  $page_number == $actual_page-1 || $page_number == $actual_page-2
  ) echo $page_number;

You can adapt it to show each 10 or so pages with % operator ...

I think using switch() case would be better in this case, I just don't remember the syntax now

Keep it Simple :)

  • 0
Reply Report

If it's possible to generate the pagination on the client, I would suggest my new Pagination plugin: http://www.xarg.org/2011/09/jquery-pagination-revised/

The solution to your question would be:

$("#pagination").paging(1000, { // Your number of elements
        format: '. - nncnn - ', // Format to get Pages: ... 3 4 [5] 6 7 ...
        onSelect: function (page) {
                // add code which gets executed when user selects a page
        },
        onFormat: function (type) {
                switch (type) {
                case 'block': // n and c
                        return '<a>' + this.value + '</a>';
                case 'fill': // -
                        return '...';
                case 'leap': // .
                        return 'Pages:';
                }
        }
});
  • 0
Reply Report

The code of the CodeIgniter pagination-class can be found on GitHub

(what you call) Smart pagination can be achieved by configuration.

$config['num_links'] = 2;

The number of "digit" links you would like before and after the selected page number. For example, the number 2 will place two digits on either side, as in the example links at the very top of this page.

  • 0
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Warm tip !!!

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