User:Xtrun/sandbox

A Wikipedia namespace is a set of Wikipedia pages whose names begin with a particular reserved word recognized by the MediaWiki software (followed by a colon). For example, in the user namespace all titles begin with the prefix User:. In the case of the article (or main) namespace, in which encyclopedia articles appear, the reserved word and colon are absent. (Note: main space articles can optionally include a colon at the beginning with no reserved word, so  and   are equivalent. This is usually only necessary for the advanced technique of transcluding a main space article into another page.)

Wikipedia has 34 current namespaces: 16 subject namespaces, 16 corresponding talk namespaces, and 2 virtual namespaces. These are all listed in the box to the right. While surfing Wikipedia, a list of namespaces is available in two clicks: do an empty search, then click Advanced under the search box. The list also makes itself available where needed in the dropdown menus of, for example, Special:Prefixindex, Special:Allpages, Special:Recentchanges, and Special:Contributions.

The aliases WP for Wikipedia, and WT for Wikipedia talk, work for page names in the search box, and making links as well as inclusions. See Aliases below for other aliases. (The pseudo-namespaces such as H for Help, and CAT for Category, are extremely limited. See Pseudo-namespaces below.)

The table on the right shows what number to use when you want to hide pages that are on your watchlist. See: Hide Pages in Watchlist for details.

Previously, the Topic namespace was available for the Flow project but it has since been turned off on this wiki.

Subject namespaces
Namespaces allow for the organization and separation of content pages from administration pages. Namespaces separate data into core sets, those intended for public viewing, and those intended for the editing community. Wikipedia's subject namespaces and their functions are listed below. A brief description is provided, but see the link for more information.

A namespace is sometimes called a space, for short, as in "Project space". A subject page and its talk page form a pair.

In use

 * Main namespace (no prefix): contains all encyclopedia articles, lists, disambiguation pages, and encyclopedia redirects. Sometimes referred to as "mainspace". Namespace alias: W:
 * User namespace (prefix User:): contains user pages and other pages created by individual users for their own personal use. Pages under this namespace can still be viewed and modified by others, so do not keep any of your sensitive data here.
 * Wikipedia namespace or Project namespace (prefix Wikipedia:): contains many types of pages connected with the Wikipedia project itself: information, policies, guidelines, essays, processes, discussion, etc. Namespace aliases: WP: or Project:
 * File namespace or Image namespace (prefix File:): contains file description pages for image, videos or audio files. These in turn have a link to their actual data file. Namespace alias: Image:
 * MediaWiki namespace (prefix MediaWiki:): a namespace containing interface texts, such as the links and messages that appear on automatically generated pages. Pages in this namespace are permanently protected. For a list of these messages, see Special:AllMessages. (The prefix cannot be shortened to "MW" because mw is an interwiki prefix. See Interwiki links below.)
 * Template namespace (prefix Template:): contains templates – pages that are intended primarily to be transcluded or substituted onto other pages to insert standard text or boxes such as infoboxes and navigation boxes.
 * Help namespace (prefix Help:): contains pages which provide help in using Wikipedia and its software, both for users of the encyclopedia and for editors.
 * Category namespace (prefix Category:): contains category pages, which display a list of pages and subcategories that have been added to a particular category, and optional additional text.
 * Portal namespace (prefix Portal:): for reader-oriented portals that help readers find articles related to a specific topic, and may contain links to encourage contributions to relevant WikiProjects. See, for example, Portal:Cricket and Portal:Spaceflight.
 * Book namespace (prefix Book:): contains entries for Wikipedia books, collections of articles about one theme, that can be used to generate downloadable files or printable documents or order books from PediaPress. (You can still create and edit a book design, but the online book rendering service has been withdrawn.)
 * Draft namespace (prefix Draft:): hosts drafts of new Wikipedia articles.
 * TimedText namespace (prefix TimedText:): synchronized subtitles for media files.
 * Module namespace (prefix Module:): contains Scribunto modules – Lua scripts implementing special-purpose parser functions for use in templates, beyond the basic set included with MediaWiki and its extensions.

Currently unused

 * Gadget namespace (prefix Gadget:): installed but not currently in use. Gadgets, which are small snippets enabled in user preferences, currently use the Mediawiki namespace with the MediaWiki:Gadget- page name prefix. It is a custom namespace installed by the Gadget extension.
 * Gadget definition namespace (prefix Gadget definition:): installed but not currently in use; see above for more information. Gadget definitions currently use the MediaWiki:Gadgets-definition page.
 * Education Program namespace (prefix Education Program:) was uninstalled in 2018, and replaced with the Programs & Events Dashboard. However, the namespace was re-added later that year to allow access to old talk pages in the     : namespace.

Not installed
On MediaWiki installations other than the English Wikipedia, additional namespaces may be installed by MediaWiki extensions; the list of default IDs for these namespaces is at Extension default namespaces.

The Flow namespace (prefix Topic:) was a proposed talk page replacement, formerly installed on English Wikipedia by Extension:StructuredDiscussions. It is no longer installed after being rejected by the community.

Aliases and pseudo-namespaces
An alias of a namespace is its namespace. For example, WP: is Wikipedia:, and so can be abbreviated. See Aliases below, for a list of aliases, such as WT: for Wikipedia talk:. A pseudo-namespace is an agreement to create redirect pages named that way, each of which is a shortcut from mainspace to a single page in its namespace. So an alias refers to any page in its namespace, but a pseudo-namespace has far fewer pages than its real namespace. There are a few pseudo-namespace names like H: for Help:, and CAT: for Category:, and these can be discovered below in the section Pseudo-namespaces.

Talk namespaces
Each of the above namespaces (but not the virtual namespaces and the former Topic: namespace) has an associated talk namespace—these are also known as discussion pages. The talk namespaces are designated by appending the word  to the namespace name. For example, the talk namespace associated with the user namespace has the prefix User talk:. The talk namespace associated with the article namespace is Talk:.

Most of the pages in the talk namespaces are used to discuss changes to the corresponding page in the associated namespace. Pages in the user talk namespace are used to leave messages for a particular user. The user talk namespace is special in that, whenever a user's talk page is edited, that user will see an orange box saying "You have new messages" on the top of every page that they view until they visit their talk page. By default, logged-in users will see a red notification square and a small orange box on the top right hand corner of the page; IP users will only see a wide orange box spanning the top of the page. (Minor edits made by bots no longer set off the new message bar. For logged-in users, the new-message bar may be disabled in Special:Preferences.)

Note that the prefix WT: expands to Wikipedia talk:, just as WP: expands to Wikipedia: (see Aliases below). For example, WT:Verifiability links to Wikipedia talk:Verifiability.

Virtual namespaces
In addition to subject namespaces, and their corresponding talk pages, there are two virtual namespaces (without corresponding talk pages) for specialist purposes:

Special
The Special: namespace consists of pages (called special pages) that are created by the software on demand, such as Special:RecentChanges. These pages can be linked as usual, as with Special:RecentChanges, except when they have parameters. To use parameters, the full URL must be given as an external link. For example, /index.php?title=Special:Recentchanges&days=3&limit=10, which returns the last ten changes in the last three days.

You can create a redirect to a Special page, but the redirect will not be followed automatically.

For a list of special pages, see Special:SpecialPages.

Media
The Media: namespace can be used to link directly to a file, rather than to the file description page.

Aliases and pseudo-namespaces
Aliases and pseudo-namespaces are not namespaces in themselves; their main role is to provide handy ways to link to actual namespaces, by providing shortened links.

The main difference between them being the way they work for this purpose; while aliases directly link to namespaces, pseudo-namespaces can only link to other namespaces by using specialist redirect pages in the main namespace called shortcuts. While aliases are also used for shortcuts, this isn't necessary if the pagename is not shortened.

Pseudo-namespaces all actually reside in main namespace; but a pseudo-namespace called Transwiki: exists as a pseudo-namespace before being moved to another namespace.

Aliases
There are six aliases defined for namespaces, all of which are case-insensitive:

If a link is made to a page title beginning with one of these strings, or if such a title is entered in the search box or used in a URL, the alias is automatically replaced by the true namespace prefix. Hence entering WP:Linking or Project:Linking is equivalent to entering Linking, and WT:Linking is equivalent to Wikipedia talk:Linking.

An alias cannot be used as the actual namespace in a page title. For example, you cannot create page WP:123; if tried, the page name is instantly converted to Wikipedia:123. It is, however, possible to change the displayed title on page Wikipedia:123 to make it WP:123 or Project:123.

This is very handy for the creation of shortcuts. For example, the shortcut for this section is WP:ALIAS, as shown in the right-side box. When the link is clicked, it automatically translated to Wikipedia:ALIAS. At this page is a redirect to Namespace. This means that the shortcut goes directly to this section from anywhere in Wikipedia. It can also be entered as an url in the browser address bar as https://en.wikipedia.org/wiki/WP:ALIAS.

Pseudo-namespaces
Аpart from Wikipedia's 32 regular namespaces and their aliases, and 2 virtual ones, there are several title prefixes appearing in shortcut redirects pointing to frequently-referred-to Wikipedia pages. These prefixes are referred to as pseudo-namespaces and include the following:


 * CAT: for shortcuts to the Category namespace. See also Category:Redirects to category space
 * H: for shortcuts to the Help namespace. See also Category:Redirects to help namespace
 * MOS: for shortcuts to the Manual of Style. See also Category:Redirects to project space
 * P: for shortcuts to the Portal namespace. See also Category:Redirects to portal space
 * T: for shortcuts to the Template namespace. See also Category:Redirects to template namespace

A more complete list is available at Shortcut.

Pseudo-namespaces are not in any way recognised by the wiki software; they are purely a community custom. Titles in pseudo-namespaces actually belong technically in the main (article) namespace and are treated as such by the software: they are case-sensitive and appear in search results restricted to the main namespace. An alias is treated like a real namespace, resulting in a search for the pagename in its namespace, but the "pseudo-namespace:pagename" search is in mainspace, not its pseudo-namespace. For example, searching for "H:S" will not search Help.

To learn some of these shortcuts, first follow the pseudo-namespace link above, then follow one of the redirects listed on that page. It will take you to the target, where you then notice any shortcut boxes to the right of the page, which may also list some additional shortcuts to that same area. By observing these steps repeatedly, you can discover ways to shorten your typing. You will use pseudo-namespace names more often if you are an advanced editor, highly active in many namespaces, or constantly linking to pages that have a pseudo-namespace shorcut.

To understand the appropriateness of redirects of this type, see Cross-namespace redirects. All shortcuts are discoverable by looking for redirects. Try the Special:Search engine Advanced interface, with the "redirects" check-box selected; there is also the category Wikipedia redirects.

As a final example, every Wikimedia Foundation project has a "Transwiki:" pseudo-namespace (sometimes a real namespace) for importing articles manually. A wiki project that would manually move many pages between sister projects uses this tag. Redirects/shortcuts are not directly involved here, as described above. Instead the page title is moved to "Transwiki:namespace:pagename", and that content is then copied and pasted into a new page name of that temporary title on the target wiki. When it is accepted the title is then moved out of the Transwiki pseudo-namespace there and becomes a real page name in its respective namespace.

Interwiki links
Wikimedia Inter-language or interwiki prefixes do not define namespaces, but point to pages in other Wikimedia projects, outside the en.wikipedia.org website. They are mentioned here because they use a namespace-like prefix technique for linking. By default, that is unless combined with another in-project namespace prefix, they link to the main namespace of the related project. Examples of such prefixes include m: (or meta:) for Meta, mw: for MediaWiki, wikt: for Wiktionary, fr: for French Wikipedia, de: for German Wikipedia, etc.

For example, m:Meta:Babel and meta:meta:Babel both link to the "Babel" page in the project namespace (second prefix) of the Meta-Wiki project (first prefix). Another example: wikt:fr:Discuter:pied/fusion daf links to the "pied/fusion daf" page in the talk namespace (3rd prefix) of French (2nd prefix) Wiktionary (1st prefix). When making links to other language Wikipedias, remember to add an initial colon if the link is intended to appear inline.

Interwiki prefixes are not just for Wikimedia projects. For example, is the interwiki link for dict.org (the DICT Development Group). For a complete list of interwiki prefixes, see the interwiki map and interwiki table.

As with aliases, it is not possible to create a page with a title beginning with an interwiki or interlanguage prefix. This includes the prefixes w: and en:, which are used in other projects to refer to English Wikipedia.

It is also not possible to create redirects to interwiki pages.

Case insensitivity
Standard namespace names, aliases and interwiki prefixes are case insensitive. The same applies to the first character after the colon. Hence the following all link to the same page:
 * Afd, Afd, Afd, afd
 * wP:Afd, wp:Afd, WP:afd
 * PROJECT:Afd, project:Afd, ProjecT:Afd, Project:afd

Namespace-dependent functionality
The namespace name is a useful variable for searching in and reporting on sets of pages. It is also used to apply features that configure the sets of pages in one namespace differently from another namespace. Using the namespace name MediaWiki can: The namespace functionality is often visible in the URL, where you will see a namespace number. These are given in the table below.
 * Search for pages in a particular namespace only.
 * Report on content or changes in content of a namespace.
 * Enable or disable the subpage feature, per namespace.
 * Offer a random article for the main page ( Special:Random ), or for a namespace  Special:Random/Namespace.
 * Change the functionality of wikilink if it targets the Category namespace or File namespace. Normally wikilinks are activated by the mouse, but Category:Pagename  activates software functionality when the page is saved, and [[File:Page name ]] activates software functionality when the page is rendered.
 * Change the functionality of so that it defaults to the set of pagenames in Template.
 * Tailor messages to a particular namespace's edit page, informing an editor of certain aspects about the content of that namespace. Such a message is different from the template message on a particular page of a namespace. Messages and are triggered by variables that can use a namespace name.

Subpages are configured for all namespaces except Main, File, MediaWiki and Category namespaces. Subpages are configured in the software by enabling or disabling the subpage feature per namespace. This further extends the function of a namespace by extending the types of pages or topics of pages a namespace can home. For example, talk page /archives are subpages, and they are both namespace searchable and page name searchable from the search box, unlike history pages, which are in no namespace. Another example is in the Template namespace where it is routine to put the documentation in a subpage called /doc.

Random pages are enabled, in the default software configuration, only for the mainspace.

Searching and reporting can operate over the entire database, or they can be limited to a namespace, and so they will offer a list of all the namespaces currently configured. Special:WhatLinksHere also offers a list of namespaces.

Programming
The 34 namespaces in the English Wikipedia are numbered for programming purposes. The prefix for each namespace is generated by a variable, using the magic word    , in the form     , as shown in the table below.

Alternative variables are available for most namespaces, for example    ,      , and      for      ,      and. The portal and book namespaces are numbered in the 100-plus range as are all MediaWiki nonstandard namespaces.

All namespaces with a positive number or zero in this list are searchable. Specifically, the     and      namespaces are not searchable.

The magic word  returns the namespace prefix of the current page. This can be used in combination with other magic words and parser functions to change the appearance of templates depending on the namespace in which they are transcluded.

Meta-templates have been created to simplify this process. These include the simple template main other, and the more complex and versatile namespace detect.

For information on changing the appearance of a page or template by namespace based on CSS, see CSS-based namespace detection on the Meta help page.