hugo/docs/content/en/functions/go-template/range.md
2024-06-21 09:41:24 +02:00

3.9 KiB

title description categories keywords action aliases toc
range Iterates over a non-empty collection, binds context (the dot) to successive elements, and executes the block.
aliases related returnType signatures
functions/go-template/break
functions/go-template/continue
functions/go-template/else
functions/go-template/end
range COLLECTION
/functions/range
true

{{% include "functions/go-template/_common/truthy-falsy.md" %}}

{{ $s := slice "foo" "bar" "baz" }}
{{ range $s }}
  {{ . }} → foo bar baz
{{ end }}

Use with the else statement:

{{ $s := slice "foo" "bar" "baz" }}
{{ range $s }}
  <p>{{ . }}</p>
{{ else }}
  <p>The collection is empty</p>
{{ end }}

Within a range block:

  • Use the continue statement to stop the innermost iteration and continue to the next iteration
  • Use the break statement to stop the innermost iteration and bypass all remaining iterations

Understanding context

At the top of a page template, the context (the dot) is a Page object. Within the range block, the context is bound to each successive element.

With this contrived example that uses the seq function to generate a slice of integers:

{{ range seq 3 }}
  {{ .Title }}
{{ end }}

Hugo will throw an error:

can't evaluate field Title in type int

The error occurs because we are trying to use the .Title method on an integer instead of a Page object. Within the range block, if we want to render the page title, we need to get the context passed into the template.

{{% note %}} Use the $ to get the context passed into the template. {{% /note %}}

This template will render the page title three times:

{{ range seq 3 }}
  {{ $.Title }}
{{ end }}

{{% note %}} Gaining a thorough understanding of context is critical for anyone writing template code. {{% /note %}}

Array or slice of scalars

This template code:

{{ $s := slice "foo" "bar" "baz" }}
{{ range $s }}
  <p>{{ . }}</p>
{{ end }}

Is rendered to:

<p>foo</p>
<p>bar</p>
<p>baz</p>

This template code:

{{ $s := slice "foo" "bar" "baz" }}
{{ range $v := $s }}
  <p>{{ $v }}</p>
{{ end }}

Is rendered to:

<p>foo</p>
<p>bar</p>
<p>baz</p>

This template code:

{{ $s := slice "foo" "bar" "baz" }}
{{ range $k, $v := $s }}
  <p>{{ $k }}: {{ $v }}</p>
{{ end }}

Is rendered to:

<p>0: foo</p>
<p>1: bar</p>
<p>2: baz</p>

Array or slice of maps

This template code:

{{ $m := slice
  (dict "name" "John" "age" 30)
  (dict "name" "Will" "age" 28)
  (dict "name" "Joey" "age" 24)
}}
{{ range $m }}
  <p>{{ .name }} is {{ .age }}</p>
{{ end }}

Is rendered to:

<p>John is 30</p>
<p>Will is 28</p>
<p>Joey is 24</p>

Array or slice of pages

This template code:

{{ range where site.RegularPages "Type" "articles" }}
  <h2><a href="{{ .RelPermalink }}">{{ .LinkTitle }}</a></h2>
{{ end }}

Is rendered to:

<h2><a href="/articles/article-3/">Article 3</a></h2>
<h2><a href="/articles/article-2/">Article 2</a></h2>
<h2><a href="/articles/article-1/">Article 1</a></h2>

Maps

This template code:

{{ $m :=  dict "name" "John" "age" 30 }}
{{ range $k, $v := $m }}
  <p>key = {{ $k }} value = {{ $v }}</p>
{{ end }}

Is rendered to:

<p>key = age value = 30</p>
<p>key = name value = John</p>

Unlike ranging over an array or slice, Hugo sorts by key when ranging over a map.

{{% include "functions/go-template/_common/text-template.md" %}}