Help:Categories

Tip Always add categories to pages and uploaded files. This way they will be easier to find, both by browsing through the categories and by searching, even more so by using external search engines, for example Google search.

Tip A good file description on file pages is a better help to finding it than adding many categories.

Note Categories are not tags. Adding more categories than necessary to a lot of pages will make it harder to find a particular page on category pages.

Through categories related pages or files can be grouped together similar to books on the same topic in a library to make it easier to find them. A category is represented by a category page listing all the pages in that category. The category pages reside in the category namespace discerned by page titles beginning with "Category:".

Pages are categorised by links to the category pages. These links are shown on the bottom of the pages, unless categories are hidden categories. The category pages are themselves categorised and form a network of related categories that can be browsed at the peril of the reader.

Searching for and browsing categories

The search box and search page

You can search specifically for categories by using beginning your search string with "Category:". Note though that the wiki is very picky about both spelling and, unfortunately, case. Another way is just search and on the results page tick the Category namespace box and search again.

Through another article

Another way, that sometimes is more effective, is to look up an article that logically should have a certain category or a related one and go to the category page from the category link at the bottom of the page, and from there browse the category structure.

The CategoryTree extension

The CategoryTree extension adds two useful features:

Subcategories on category pages are made expandable. Click on any blue triangles.
Subcategories can be browsed with the CategoryTree tool. Try for example Special:CategoryTree/Root category.

Categorizing pages

To add a page (be it an article, an image or any other editable page) to a category, add the following wiki markup to the end of the page, just before the language links to translated pages.

[[Category:Category name]]

Quick guide to categorising

Find appropriate categories
- By searching (see #Searching for and browsing categories)
- By checking how similar pages or images are categorized (though some may not yet have been categorized)
- Starting a category, check its parent or sub-categories to find an appropriate category. Avoid picking too general categories.
Add categories to the page or file
- By selecting them on the upload form or in the wizard
- By manually adding for example [[Category:Foobar]] to the bottom of the page or file description page

A note about subcategories

Use a category that is as specific as possible, unless of course there would only be some few pages in that category. If there is a subcategory, please use that subcategory instead of its parent category and use only the subcategory. The reason for this is that the category page of the parent category would otherwise be more cluttered and that finding a certain page in that category will be more difficult.

Category sorting

Sometimes you want a page to be sorted under a different name on the category page. This can be done using a vertical stroke or pipe and sort key in the category link, or by using the magic word {{DEFAULTSORT}}.

Using a sort key

If there is only a few category links, or if the page for some reason is to be sorted differently in different categories using piped category links is preferable. The sort key are then used after a pipe or vertical stroke as below:

[[Category:Category name|Sort key]]

For example like below:

[[Category:Boeing|707-320]]

Using a default sort key

If a page have several categories it is probably easier to use the magic word {{DEFAULTSORT:}}:

{{DEFAULTSORT:Sort key}}

For example like the below examples:

{{DEFAULTSORT:707-320}}

or

{{DEFAULTSORT:Last name, First name}}

Do note that the default sort key should preferably be on top of a page as the last one on a page will override any other category sorting, including category sorting by templates.

Linking to category pages

Linking to category pages can be done like below. Do note that the category name have to be preceded by a colon. A regular link will add the page to that category (see #Categorizing pages).

Description	What you type	What you get
Linking to a category must be done with a preceding colon (:).	[[:Category:Help]]	Category:Help
Links to categories can use a pipe (\|) as well.	See the [[:Category:Help\|help]] category.	See the help category.

External links

WikiMedia Meta-Wiki: Help:Categories