collections.Union
Syntax
collections.Union SET1 SET2
Returns
any
Alias
union
Given two arrays (or slices) A and B, this function will return a new array that contains the elements or objects that belong to either A or to B or to both.
{{ union (slice 1 2 3) (slice 3 4 5) }}
<!-- returns [1 2 3 4 5] -->
{{ union (slice 1 2 3) nil }}
<!-- returns [1 2 3] -->
{{ union nil (slice 1 2 3) }}
<!-- returns [1 2 3] -->
{{ union nil nil }}
<!-- returns an error because both arrays/slices have to be of the same type -->
OR filter in where query
This is also very useful to use as OR filters when combined with where:
{{ $pages := where .Site.RegularPages "Type" "not in" (slice "page" "about") }}
{{ $pages = $pages | union (where .Site.RegularPages "Params.pinned" true) }}
{{ $pages = $pages | intersect (where .Site.RegularPages "Params.images" "!=" nil) }}
The above fetches regular pages not of page or about type unless they are pinned. And finally, we exclude all pages with no images set in Page parameters.
See intersect for AND.