Nodyn:Ifempty/doc

This is the {{ifempty}} template.

This template is used inside other templates. It takes up to nine parameters (parameters 1-9), and returns the first one that is defined and non-empty, otherwise nothing. Typical usage is like this:

{{ifempty| {{{logo|}}} | {{{image|}}} | default.svg }}

This returns the first of the parameters logo and image that is defined and non-empty, otherwise "default.svg".

Background

The MediaWiki parameter default function doesn't return the default value for empty parameters. That is, {{{logo|default.svg}}} does not return "default.svg" if the template was called like this: {{template|logo=}}.

The usual workaround is to do like this:

{{#if:{{{logo|}}}| {{{logo}}} | default.svg }}

But this becomes complex when you want to check several parameters:

{{#if:{{{logo|}}}| {{{logo}}} | {{#if:{{{image|}}} | {{{image}}} | default.svg }}}}

Then it is easier to use this template instead:

{{ifempty| {{{logo|}}} | {{{image|}}} | default.svg }}

Note! The parameters to {{ifempty}} must use the pipe "|", like this: {{{logo|}}}. Or else {{ifempty}} will be fed and return the string "{{{logo}}}" if logo was not defined.

Examples

Code	Result	Comment
{{ifempty}}		Returns an empty string.
{{ifempty|one}}		Returns the first parameter that is defined and not empty.
{{ifempty|one|two}}
{{ifempty|one|two|three|four}}
{{ifempty||two}}		The first parameter was empty or undefined, so uses the next parameter.
{{ifempty||two|three|four}}
{{ifempty||two||four}}
{{ifempty|||||||||nine}}
{{ifempty||||||||||ten}}		Only handles up to nine parameters, so returns an empty string.
{{ifempty|}}		The only parameter is empty or undefined, so returns an empty string.
{{ifempty||||}}		Returns an empty string.
{{ifempty|{{{1|}}}|{{{2|}}}|three}}
{{ifempty|{{{1}}}|{{{2}}}|three}}		Returns the text "{{{1}}}", because it is a non-empty string. Note the lack of "|" in the first two parameters.
{{ifempty|{{{logo|}}}|two}}
{{ifempty|{{{logo}}}|two}}		Returns the text "{{{logo}}}", because it is a non-empty string. Note the lack of "|" in the first parameter.
{{ifempty|2=x}}		Whether parameter 1 is undefined or empty does not matter.
{{ifempty|p=q}}		The template checks its parameters 1-9, not other ones.

See also

• {{px}} – Helps handling image width parameters in templates.
• Help:Parameter default – You probably don't need to know this anymore if you use this template.