Template:If then show

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This template tests whether the first unnamed parameter is not an empty string and returns it if it is not empty. Otherwise it returns the second unnamed parameter.

This is useful when the first parameter is a {{#invoke: }} of a Lua module that may return a value or nothing. Because it uses the {{#invoke: }} just once, it simplifies the coding of infoboxes, for example.

The optional third and fourth unnamed parameters provide a prefix and a suffix for the first parameter when returned. This enables the designer to construct more complex templates that still only use one invoke of a Lua module.

Usage[edit source]

Lua error in Module:Wikibase at line 40: attempt to index field 'wikibase' (a nil value). (P26) for Lua error in Module:Wikibase at line 40: attempt to index field 'wikibase' (a nil value). (Q151973)
{{If then show|{{#invoke:WikidataIB|getValue|P26|qid=Q151973|fwd=ALL|osd=no}}|unmarried}}Lua error in Module:WikidataIB at line 762: attempt to index field 'wikibase' (a nil value).
Lua error in Module:Wikibase at line 40: attempt to index field 'wikibase' (a nil value). (P26) for Lua error in Module:Wikibase at line 40: attempt to index field 'wikibase' (a nil value). (Q905)
{{If then show|{{#invoke:WikidataIB|getValue|P26|qid=Q905|fwd=ALL|osd=no}}|unmarried}}Lua error in Module:WikidataIB at line 762: attempt to index field 'wikibase' (a nil value).

Prefix and suffix[edit source]

Infobox field with microformat[edit source]

A value in an infobox can be designed to be wrapped in a microformat if the wikidata call is not empty:

{{if then show | {{#invoke:WikidataIB | getValue | rank=best |P19 |name=birth_place |qid={{{qid|}}} |suppressfields={{{suppressfields|}}} |fetchwikidata={{{fetchwikidata|}}} |noicon={{{noicon|}}} | {{{birth_place|}}} }} || <span class="birthplace"> | </span>}}
If there is a local parameter supplied in the article (e.g. |birth_place=London), the code will return <span class="birthplace">London</span>.
If there is no local parameter it will attempt to fetch a value for Lua error in Module:Wikibase at line 40: attempt to index field 'wikibase' (a nil value). (P19) from Wikidata.
If that has a value, such as "New York", the code will return <span class="birthplace">New York</span>.
If there is no value returned from Wikidata, the code returns nothing.

Table[edit source]

A table can be designed to display a row only when a particular property of the article exists on Wikidata.

Lua error in Module:Wikibase at line 40: attempt to index field 'wikibase' (a nil value). (P26) for Lua error in Module:Wikibase at line 40: attempt to index field 'wikibase' (a nil value). (Q151973)
{| class="wikitable"
|-
! scope="col" style="width:15em;" | Label
! scope="col" style="width:36em;" | Value
{{If then show|{{#invoke:WikidataIB|getValue|P26|qid=Q151973|fwd=ALL|osd=no}}||<tr><th>{{#invoke:WikidataIB|getLabel|P26|qid=Q151973}}</th><td>|</td></tr>}}
|}
Label Value
Lua error in Module:WikidataIB at line 533: attempt to index field 'wikibase' (a nil value).Lua error in Module:WikidataIB at line 762: attempt to index field 'wikibase' (a nil value).
Lua error in Module:Wikibase at line 40: attempt to index field 'wikibase' (a nil value). (P26) for Lua error in Module:Wikibase at line 40: attempt to index field 'wikibase' (a nil value). (Q905)
{| class="wikitable"
|-
! scope="col" style="width:15em;" | Label
! scope="col" style="width:36em;" | Value
{{If then show|{{#invoke:WikidataIB|getValue|P26|qid=Q905|fwd=ALL|osd=no}}||<tr><th>{{#invoke:WikidataIB|getLabel|P26|qid=Q905}}</th><td>|</td></tr>}}
|}
Label Value
Lua error in Module:WikidataIB at line 533: attempt to index field 'wikibase' (a nil value).Lua error in Module:WikidataIB at line 762: attempt to index field 'wikibase' (a nil value).

See also[edit source]

Template:Ifnoteq then show
tests whether the first unnamed parameter is equal to the second unnamed parameter and returns the third unnamed parameter if it does. Otherwise it returns the first unnamed parameter. This is useful when the first parameter is a {{#invoke: of a Lua module that returns a value for which a specific exception is required.
Template:If then wikilink
tests whether the first unnamed parameter is not an empty string and if it isn't, it returns the parameter formatted as piped wiki-link using an optional namespace prefix.
Template:Formatter link
takes an external identifier code as |code= and uses a formatter url as |url= to construct a link to the external resource, which uses the code as display.
Template:Emptyor
tests a piece of text to ascertain whether it's effectively empty or contains some text. If the unnamed parameter consists only of html tags, punctuation (e.g. Wiki-markup) and whitespace, then Emptyor returns nothing; otherwise it returns the parameter unchanged. Wrapper for p.emptyor function.

External links[edit source]