mirror of
https://github.com/gohugoio/hugo.git
synced 2024-07-08 01:56:15 +00:00
5fd1e74903
``` git subtree add --prefix=docs/ https://github.com/gohugoio/hugoDocs.git master --squash ``` Closes #11925
81 lines
2.1 KiB
Markdown
81 lines
2.1 KiB
Markdown
---
|
|
title: collections.Complement
|
|
description: Returns the elements of the last collection that are not in any of the others.
|
|
categories: []
|
|
keywords: []
|
|
action:
|
|
aliases: [complement]
|
|
related:
|
|
- functions/collections/Intersect
|
|
- functions/collections/SymDiff
|
|
- functions/collections/Union
|
|
returnType: any
|
|
signatures: ['collections.Complement COLLECTION [COLLECTION...]']
|
|
aliases: [/functions/complement]
|
|
---
|
|
|
|
To find the elements within `$c3` that do not exist in `$c1` or `$c2`:
|
|
|
|
```go-html-template
|
|
{{ $c1 := slice 3 }}
|
|
{{ $c2 := slice 4 5 }}
|
|
{{ $c3 := slice 1 2 3 4 5 }}
|
|
|
|
{{ complement $c1 $c2 $c3 }} → [1 2]
|
|
```
|
|
|
|
{{% note %}}
|
|
Make your code simpler to understand by using a [chained pipeline]:
|
|
|
|
[chained pipeline]: https://pkg.go.dev/text/template#hdr-Pipelines
|
|
{{% /note %}}
|
|
|
|
```go-html-template
|
|
{{ $c3 | complement $c1 $c2 }} → [1 2]
|
|
```
|
|
|
|
You can also use the `complement` function with page collections. Let's say your site has five content types:
|
|
|
|
```text
|
|
content/
|
|
├── blog/
|
|
├── books/
|
|
├── faqs/
|
|
├── films/
|
|
└── songs/
|
|
```
|
|
|
|
To list everything except blog articles (`blog`) and frequently asked questions (`faqs`):
|
|
|
|
```go-html-template
|
|
{{ $blog := where site.RegularPages "Type" "blog" }}
|
|
{{ $faqs := where site.RegularPages "Type" "faqs" }}
|
|
{{ range site.RegularPages | complement $blog $faqs }}
|
|
<a href="{{ .RelPermalink }}">{{ .LinkTitle }}</a>
|
|
{{ end }}
|
|
```
|
|
|
|
{{% note %}}
|
|
Although the example above demonstrates the `complement` function, you could use the [`where`] function as well:
|
|
|
|
[`where`]: /functions/collections/where
|
|
{{% /note %}}
|
|
|
|
```go-html-template
|
|
{{ range where site.RegularPages "Type" "not in" (slice "blog" "faqs") }}
|
|
<a href="{{ .RelPermalink }}">{{ .LinkTitle }}</a>
|
|
{{ end }}
|
|
```
|
|
|
|
In this example we use the `complement` function to remove [stop words] from a sentence:
|
|
|
|
```go-html-template
|
|
{{ $text := "The quick brown fox jumps over the lazy dog" }}
|
|
{{ $stopWords := slice "a" "an" "in" "over" "the" "under" }}
|
|
{{ $filtered := split $text " " | complement $stopWords }}
|
|
|
|
{{ delimit $filtered " " }} → The quick brown fox jumps lazy dog
|
|
```
|
|
|
|
[stop words]: https://en.wikipedia.org/wiki/Stop_word
|