Template:If then show/doc

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

spouse (P26) for Richard Burton (Q151973)

{{If then show|{{#invoke:WikidataIB|getValue|P26|qid=Q151973|fwd=ALL|osd=no}}|unmarried}} → Elizabeth Taylor, Sybil Christopher, Suzy Miller, Elizabeth Taylor, Sally Burton 

spouse (P26) for Franz Kafka (Q905)

{{If then show|{{#invoke:WikidataIB|getValue|P26|qid=Q905|fwd=ALL|osd=no}}|unmarried}} → unmarried

Prefix and suffix

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

spouse (P26) for Richard Burton (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
spouse	Elizabeth Taylor, Sybil Christopher, Suzy Miller, Elizabeth Taylor, Sally Burton

spouse (P26) for Franz Kafka (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