Scratchpad:Categories

Categories are a software feature of MediaWiki providing automatic indexes that are useful as tables of contents.

You can categorize pages and files by adding one or more Category tags to the content text. These tags create links at the bottom of the page that take you to the list of all pages in that category, which makes it easy to browse related articles.

Summary
Each of the pages in the Category namespace represents a so-called category, a grouping of related pages, and contains an index for the pages of its category. For example, this page belongs to “Category:Help”. If you open the “Category:Help” page, you will see a link to this page there.

When a page belongs to one or more categories, these categories appear at the bottom of the page (or in the upper-right corner, depending on the skin being used).

The category pages themselves contain 2 parts :
 * at their beginning, an optional part may contain text that can be edited, like any other page,
 * at their end, an ever present, automatically generated, alphabetical list of all pages in that category, in the form of links. (In fact, in ASCII order. See mw:Help:Special pages).

To assign a category to a page, simply add the link   to the page’s wikitext. The usual place to add it is at the bottom of the page.

To link a category page within a page as a normal wikilink (without adding the page to the actual category), prefix the link name with a colon. For example:  .

New categories can be created before assigning any page to it, in the same way as any other regular page.

Individual wikis may have their own top-level categories, such as Category:Contents at Wikipedia.

For a complete list of all categories which have at least one page, see Special:Categories.

For a complete list of all categories, including the ones that do not have any pages, see Special:Allpages/Category :  (note the colon at the end).

Adding a page to a category
To add a page or uploaded file to a category, simply edit the page, and add the following text (where Name is the name of the category you want to add it to).



Any number of     tags may be added to the page and the page will be listed in all of them. tags are usually added at the very bottom of the page for the convenience of other editors.

Sort key
By default, a page is sorted under the first letter of its full name including the namespace. (This corresponds to filing under the   magic word.) Also, MediaWiki groups accented characters separately from their unaccented version, so pages starting by À, Á, Ä, will be listed under separate headings, instead of under heading A.

A sort key specifies under which letter heading, and where in the category list, the page will appear. You can add a sort key by placing it inside the tag after a pipe character. For example, the tag below will add the page under heading "S".

Sort

(This corresponds to filing under the   magic word.)

Sort keys are case-sensitive, and spaces and other characters are also valid. The order of the sections within a category follows the Unicode sort order. The sort key does not change the page title displayed in the category.

Magic words
The benefit of using magic words is that it is dynamic and changes with the name of the category and/or namespace.

The chart below gives examples of how the two magic words referred to here would represent this page.

Creating a category page
Categories exist even if their page has not been created, but these categories are isolated from others and serve little purpose for organization or navigation.

A category is created by creating a page in the Category: namespace. A category page can be created the same way as other wiki pages (see Help:New page); just add   before the page title.

To avoid extra work, try searching within your wiki before creating a new category. The list of all categories can be found at Special:Categories (both created and awaiting creation) and Special:Allpages/Category: (created only).

Unlike other wiki pages, it is not possible to rename (move) a category. It is necessary to create a new category and change the     tag on each and every page. The new category will not have the older category's page history, which is undesirable if there are many revisions.

Managing the category hierarchy
Categories may belong to other categories in a hierarchy. Since category pages are much like any other page, a     tag may be added to the bottom of a category page.

It is a good idea to organize all categories into a hierarchy with a single top level category. The category structure can take the form of a tree with separate branches, but more often will have a graph structure. Generally, there should be a contiguous chain of parent-child links between each category and the top level category.

Hidden categories
Hidden categories are little used on Scratchpad.

The categories that a page is in are normally listed at the bottom of the page. A category can be hidden from this list by adding the magic word “ ” to the category page. Hidden categories are not hidden from category pages (Bug 15550).

Users can choose to see hidden categories in a separate “” list, by checking “” in the “” section of Special:Preferences.

Hidden categories are automatically added to Category:. This category is specified in the system message MediaWiki:Hidden-category-category.

Linking to a category
To create a link to a category, use a leading colon before the category name (without this colon, the current page would be added to the category):


 * &rarr;    :Help

To change the link text, write the text inside the link tag after a pipe:


 * &rarr; Help category

Redirect pages that redirect to categories must also use the colon, otherwise they will be added to the category instead of redirecting.

Redirecting a category
Like normal wiki pages, category pages can be redirected to other normal or category pages.

It is preferred to redirect categories using the template.

Why a category list might not be up to date
Sometimes, pages are not placed in categories manually by Scratchpad editors, but by means of templates, which can be used to place identical information (including category membership information) on many different pages at once. When the information on such a template is edited, the pages containing that template are updated, but not necessarily updated immediately. This means that pages might not always appear in the most current categories. However, this problem usually affects project maintenance categories rather than the categories used for browsing.

Various other temporary delays may sometimes mean that lists of category members, subcategories, and/or the page counts given, are not completely up to date. So, if you are editing Admin Tools Wiki and find that your page has not yet shown up in a category, or been removed from an old category, don't panic! The problem may resolve itself within minutes, but sometimes it may take longer, in some cases days, even weeks. (It may help if you purge the page.)