Help:Conditional tables

• Help:Table
• Wikitext
  • Intro
  • Editing
  • Expanding
  • Summary
• VisualEditor
  • Intro
  • Editing
  • Adding
  • Expanding
  • Summary
• Basics
  • Creation
  • Locations
• Advanced
  • Sortable
  • Formatting
  • Collapsing
  • Conditional
  • History
• Category
  • Templates
• MOS
  • Accessibility
  • Tutorial

There are three ways to conditionally display or hide rows within a table. All of the methods involve the use of parser conditionals, in particular, the parser #if statement (see the § Refresher section) to conditionally include or exclude a row, depending on the value of some expression.

Methods

CSS display:none property

The simplest option is to use the conditional with the CSS "display:none" property:

{| class="wikitable"
|- {{#if: {{{variable_foo|}}} | | style="display: none;" }}
! Foo
| {{{variable_foo}}}
|-
! Bar
| {{{variable_bar}}}
|}

The code above is in {{Conditional tables/example 2c}}. The table below demonstrates the effect when it is used:

Template call	Result
{{Conditional tables/example 2c|variable_bar=bar}}	Foo {{{variable_foo}}} Bar bar
{{Conditional tables/example 2c|variable_foo=|variable_bar=bar}}	Foo Bar bar
{{Conditional tables/example 2c|variable_foo=foo}}	Foo foo Bar {{{variable_bar}}}
{{Conditional tables/example 2c|variable_foo=foo|variable_bar=bar}}	Foo foo Bar bar

Pros and cons: with this method, there is no need for the wikitable pipe character to appear in the #if conditional, thus avoiding issues with escaping the vertical bar . However, sources and notes referred to in the hidden cells won't get suppressed with the other contents, so they will continue to be listed at the end of an article without any references to them occurring in the article's text.

HTML tables

One method of hiding rows in tables (or other structures within tables) uses HTML directly. In general, there are only a handful of HTML tags you need to be aware of

• <tr> - this tag creates a new row (similar to |- in MediaWiki table syntax)
• <th> - this tag creates a new header cell within a row (similar to ! in MediaWiki table syntax)
• <td> - this tag creates a new cell within a row (similar to | in MediaWiki table syntax)
• <caption> - this tag creates a caption (similar to |+ in MediaWiki table syntax)

A sample HTML table with a conditional row based on testing a template variable with #if follows:

{| class="wikitable"
{{#if:{{{variable_foo|}}}
|<tr><th>Foo</th><td>{{{variable_foo}}}</td></tr>}}
|-
! Bar
| {{{variable_bar}}}
|}

The code above is in {{Conditional tables/example 2a}}. As before, the table below demonstrates the effect when it's used:

Template call	Result
{{Conditional tables/example 2a}}	Bar {{{variable_bar}}}
{{Conditional tables/example 2a|variable_foo=}}	Bar {{{variable_bar}}}
{{Conditional tables/example 2a|variable_foo=|variable_bar=bar}}	Bar bar
{{Conditional tables/example 2a|variable_foo=value}}	Foo value Bar {{{variable_bar}}}
{{Conditional tables/example 2a|variable_foo=value|variable_bar=bar}}	Foo value Bar bar

Vertical bar escaping

Because the parser function #if and MediaWiki table syntax do not work together well, the template code described at § Pitfalls with an illustration of non-working code at Example 2 will not work correctly. The problems there can be rectified by properly escaping the vertical bar.

For most characters, often it's good enough to replace a problematic characters with the corresponding HTML entities, e.g. "{" by {, "|" by |, and "}" by }. But for Wiki tables a real vertical bar character "|" is required — using | HTML entity does not work.

A simple trick allows to protect the "|" in template parameter values while still arriving as real "|" delimiter in the Wiki table, see the magic word {{!}}. Note that "!" (exclamation mark) has no problems with templates, it's the other delimiter used in Wiki tables. Here's the code for plan B:

{| class="wikitable"
{{#if:{{{foo|}}}|
{{!}}-
! Foo
{{!}} {{{foo}}}
}}
|-
! Bar
| {{{bar}}}
|}

The code above is in {{Conditional tables/example 2b}}. As before, the table below demonstrates the effect when it's used:

Template call	Result
{{Conditional tables/example 2b|bar=nobar}}	Bar nobar
{{Conditional tables/example 2b|foo=|bar=vbar}}	Bar vbar
{{Conditional tables/example 2b|foo=value}}	Foo value Bar {{{bar}}}
{{Conditional tables/example 2b|foo=value|bar=vbar}}	Foo value Bar vbar

Refresher on parser functions

Further information: mw:Help:Magic words § Parser functions, and mw:Help:Extension:ParserFunctions

Conditional parser functions like #if allow for the conditional display of table rows, columns or cells, but they have some limits.

The following example shows a basic use for #if that is available from the extension ParserFunctions:

 {{#if: {{{variable_foo|}}}
   |foo is set to '''{{{variable_foo}}}'''
   |foo is ''blank''
 }}

Here, {{{variable_foo}}} is checked to see if it is defined with a non-blank value. The table below shows the output from a template call (we'll call the template {{Conditional tables/example 1}}) with different values for {{{variable_foo}}}:

Template call	Result
{{Conditional tables/example 1}}	foo is blank
{{Conditional tables/example 1|variable_foo=}}	foo is blank
{{Conditional tables/example 1|variable_foo=value}}	foo is set to value

Positional parameters {{{1}}} etc. work like named parameters:

 {{#if:{{{1|}}}
 |1st parameter is '''{{{1}}}'''
 |1st parameter is ''blank''}}

Template call	Result
{{Conditional tables/example 1b||bar}}	1st parameter is blank
{{Conditional tables/example 1b|foo|bar}}	1st parameter is foo
{{Conditional tables/example 1b|[[m:|not empty]]}}	1st parameter is not empty
{{Conditional tables/example 1b|bad=idea}}	1st parameter is blank
{{Conditional tables/example 1b|1=ok=yes}}	1st parameter is ok=yes

Note how the pipe symbol (vertical bar) in the link works as is, it's not quite that easy within Wiki tables, see below.

Pitfalls

Parser functions and table syntax

Unfortunately #if and the MediaWiki table syntax do not work together well. For example, the following, {{Conditional tables/example 2}} is invalid and will not work:

{| class="wikitable"
{{#if:{{{variable_foo|}}}
|
|-
! Foo
| {{{variable_foo}}}
}}
|-
! Bar
| {{{variable_bar}}}
|}

The table below demonstrates the effect when {{Conditional tables/example 2}} is used:

Template call	Result
{{Conditional tables/example 2}}	Foo Bar {{{variable_bar}}}
{{Conditional tables/example 2|variable_foo=}}	Foo Bar {{{variable_bar}}}
{{Conditional tables/example 2|variable_foo=|variable_bar=bar}}	Foo Bar bar
{{Conditional tables/example 2|variable_foo=value}}	Bar {{{variable_bar}}}
{{Conditional tables/example 2|variable_foo=value|variable_bar=bar}}	Bar bar

The problem is with the usage of the pipe character (|). This character, in template calls, is used to separate parameters and so is invalid.

Getting help

If you find yourself unable to get a template to behave how you like, you can try asking on Village pump, placing a request at Requested templates, or contacting an editor via IRC.

See also

For avoiding blank rows in the case of successive optional rows, see m:Help:Table#Conditional table row.

For more information on #if (and other # functions), see:

• mw:Help:Extension:ParserFunctions

The following help topics deal with templates:

• m:Help:Template
• m:Help:Advanced templates

This help topic deals with table design (since most templates use tables, this may be useful):

• Help:Table

And finally:

• Help:Conditional expressions