User:Anon126/How-to/Templates

Main Templates

See also: Help:Template

{{...}}

The code that keeps Wikipedia running smoothly

If you've been editing Wikipedia, there's no doubt that you've seen this code: some text between double braces. These are templates. Knowing how to use templates is important for editing Wikipedia.

What are templates for?

Templates contain pieces of code that are used over and over again. It would be tedious to enter this every single time it was used, so a shorter bit of code that refers to the template is used instead.

The simplest case

The easiest (and probably most common) way to use a template is to add double braces around the template name, like so:

{{Example}}

This produces:

This is an example of a template. For help with templates, see Help:Template.

As with articles on Wikipedia, the case of the first letter doesn't matter, so {{example}} does the same thing.

Adding a template in this way has a technical name, transclusion. What this means is that the software automatically fetches the code for the template and displays it on the page. If the template is updated, then the page with the transcluded template will update as well.

Where is the template code?

You might think that the code for the template above would be fetched from Example. But that's an article about examples. So where did that box come from?

Answer: Template:Example. Pages starting with Template: are reserved for making templates.

The page should also have documentation, that is, information about how and when to use the template. So if you're ever curious about a template, add Template: to the beginning to check it out.

Non-Template: templates

It is possible to transclude pages that don't start with Template:. Templates are not required to have such a name. It's also possible to transclude pages that aren't templates (the software makes no distinction), but this is not recommended.

To transclude an article (not recommended), add a colon inside the parentheses:

{{:example}}

To save space I've included the transclusion in this box.

Example may refer to: exempli gratia (e.g.), usually read out in English as "for example" .example, reserved as a domain name that may not be installed as a top-level domain of the Internet example.com, example.net, example.org, example.edu, second-level domain names reserved for use in documentation as examples HMS Example (P165), an Archer-class patrol and training vessel of the Royal Navy Arts The Example, a 1634 play by James Shirley The Example (comics), a 2009 graphic novel by Tom Taylor and Colin Wilson Example (musician), the British dance musician Elliot John Gleave (born 1982) Example (album), a 1995 album by American rock band For Squirrels See also  Example portal Exemplar (disambiguation), a prototype or model which others can use to understand a topic better Exemplum, medieval collections of short stories to be told in sermons Eixample, an inner suburb of Barcelona with distinctive architecture

To transclude a non-article (including templates that don't start with Template:), use the full page name:

{{Wikipedia:Help desk/Header}}

This is the header code for the help desk. It's not exactly a template, but it is supposed to be transcluded. Again, I've used this box to save space.

Welcome—ask questions about how to use or edit Wikipedia! (Am I in the right place?) For other types of questions, use the search box, see the reference desk or Help:Contents. If you have comments about a specific article, use that article's talk page. Do not provide your email address or any other contact information. Answers will be provided on this page only. Check back on this page to see if your question has been answered. For real-time help, use our IRC help channel, #wikipedia-en-help. New editors may prefer the Teahouse, a help area for beginners. Ask a question

Parameters

Sometimes additional information is added to change how the template looks or acts. These are parameters, and the additional information provided is a parameter's value. They take the form:

{{example|Parameter value|Another parameter value}}

Vertical bars (also called "pipes") are used to separate the name of the template and the parameters. The text of parameters can be displayed or used as an option to determine other aspects of appearance. The documentation on the template page should explain exactly what each parameter does.

Sometimes parameters have names. These look like:

{{example|Name=Value}}

Named parameters can be given in any order, while unnamed parameters must be given in a specific order. Unnamed parameters can also have "names," which are 1, 2, 3, and so on. So it is technically possible to use:

{{example|2="Second" parameter|1="First" parameter}}

But this gets confusing, so please don't.

Special characters

If a parameter value has an equals sign, that becomes a problem for unnamed parameters. Take this example:

{{example|1+1=2}}

What you want is for the first unnamed parameter to have the value 1+1=2, but the software actually sees this as a parameter with the name 1+1 and the value 2.

There are two ways to fix this:

1. Convert it into a named parameter with the number-name trick:
   

   {{example|1=1+1=2}}

2. Use the template {{=}}, which is designed for equals signs in parameter values:
   

   {{example|1+1{{=}}2}}

If a parameter value has a vertical bar, the way to get around it is to use {{!}}. (That is an exclamation mark, not a literal vertical bar.)

Substitution

Substitution is the other way to include a template in a page, as opposed to transclusion. Instead of fetching the template code every time, the template code is actually included in the page itself. This means that once a template is substituted onto the page, it will not be updated if the template changes.

To do this, add subst: before the template name.

{{subst:example}}

This achieves the same result:

This is an example of a template. For help with templates, see Help:Template.

But when the the page was saved, the template was replaced with its code. Again, the template code will not be updated, so if Template:Example is updated after this page was written, the first box (transcluded) will be updated, but the second one (substituted) will not. (For the record, this version was used.)

Transclusion versus substitution

Templates can change, and often they are improved. So why substitute a template? There are a few reasons:

• Discussion messages: In a discussion (such as on a talk page), substituting templates allows for a static record. This ensures that when others look through the history or an archive, they will see exactly what the participants saw.
  • Exceptions are {{talkback}} and a few others, which specifically say "you can remove the {{...}} template". Obviously if the template is substituted, then this note doesn't make sense, so these templates should be transcluded.
• Technical purposes: Some templates must be substituted to take advantage of technical features. Such features are many, and beyond the scope of this page. The documentation for the template will state when a template must be substituted, so just check the template page for what to do.

If a template does not meet these conditions, it should be transcluded. Some templates even have to be transcluded for technical purposes. (Again, check the documentation.)