Restricting the number of list items? [closed]

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. 开发者_如何学Go Closed 9 years ago.

What I'm aiming for is a limit on the number of list items on one page, and then for them to be transfered onto a new page. I want to do this so I can add new list items quickly and without worrying if the page is too long/takes too long to load. A point in the right direction would be great, and an example of the code I need would be better! Thank you

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The general technique is called paging. See, for example, http://www.php-mysql-tutorial.com/wikis/php-tutorial/paging-using-php.aspx

The idea is to use a LIMIT clause in your SQL database query to retrieve a subset of results, specified by an offset within the list of records and the number of records starting at that offset to retrieve. You then modify gallery.php to accept a page GET parameter (as the tutorial that I linked to does; i.e. gallery.php?page=3) or an offset GET parameter (i.e. gallery.php?offset=36) and modify the LIMIT clause appropriately. For example, if you have 12 items to a page, then page 2 of the gallery displays records 12 through 23 inclusive (counting from zero).

EDIT: Here is example PHP code:

<ul class="ulgallery">
<?php

$gallery_items = array(
    array("img_src" => "image1.png", "title" => "This is image 1.", "author" => "John Doe"),
    array("img_src" => "image2.png", "title" => "This is image 2.", "author" => "John Doe"),
    array("img_src" => "image3.png", "title" => "This is image 3.", "author" => "John Doe"),
    array("img_src" => "image4.png", "title" => "This is image 4.", "author" => "John Doe"),
    array("img_src" => "image5.png", "title" => "This is image 5.", "author" => "John Doe"),
    array("img_src" => "image6.png", "title" => "This is image 6.", "author" => "John Doe"),
    array("img_src" => "image7.png", "title" => "This is image 7.", "author" => "John Doe"),
    array("img_src" => "image8.png", "title" => "This is image 8.", "author" => "John Doe"),
    array("img_src" => "image9.png", "title" => "This is image 9.", "author" => "John Doe"),
    array("img_src" => "image10.png", "title" => "This is image 10.", "author" => "John Doe"),
    array("img_src" => "image11.png", "title" => "This is image 11.", "author" => "John Doe"),
    array("img_src" => "image12.png", "title" => "This is image 12.", "author" => "John Doe"),
    array("img_src" => "image13.png", "title" => "This is image 13.", "author" => "John Doe"),
    // ...
    array("img_src" => "image304.png", "title" => "This is image 304.", "author" => "John Doe")
);

define("ITEMS_PER_PAGE", 12);

$page = isset($_GET["page"]) ? (int)$_GET["page"] : 0;
if ($page < 0)
    $page = 0;

$num_pages = (int)((count($gallery_items) + ITEMS_PER_PAGE - 1) / ITEMS_PER_PAGE);
if ($page > $num_pages)
    $page = $num_pages;

$end_index = ($page + 1) * ITEMS_PER_PAGE;
if ($end_index > count($gallery_items))
    $end_index = count($gallery_items);
for ($offset = $page * ITEMS_PER_PAGE; $offset < $end_index; ++$offset) {
    $current_gallery_item = $gallery_items[$offset];
    // output the <img> tag for $gallery_items[$offset];
    echo '<li><a href="#"><img src="' . $current_gallery_item["img_src"] . '" /></a></li>';
}
?>
</ul>

I haven't tested it, but it is along the lines of what I am suggesting.