range - Hugo — ContextQMD

The collection may be a slice, a map, or an integer.

go-html-template

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

Use with the else statement:

go-html-template

{{ $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

See the context section in the introduction to templating.

For example, 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:

go-html-template

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

Hugo will throw an error:

text

can't evaluate field Title in type int

The error occurs because we are trying to use the .Title method on a string 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.

This template will render the page title three times:

go-html-template

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

[!note] Gaining a thorough understanding of context is critical for anyone writing template code.

Examples

Slice of scalars

This template code:

go-html-template

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

Is rendered to:

html

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

This template code:

go-html-template

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

Is rendered to:

html

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

This template code:

go-html-template

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

Is rendered to:

html

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

Slice of maps

This template code:

go-html-template

{{ $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:

html

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

Slice of pages

This template code:

go-html-template

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

Is rendered to:

html

<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:

go-html-template

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

Is rendered to:

go-html-template

<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.

Integers

Ranging over a positive integer n executes the block n times, with the context starting at zero and incrementing by one in each iteration.

go-html-template

{{ $s := slice }}
{{ range 1 }}
  {{ $s = $s | append . }}
{{ end }}
{{ $s }} → [0]

go-html-template

{{ $s := slice }}
{{ range 3 }}
  {{ $s = $s | append . }}
{{ end }}
{{ $s }} → [0 1 2]

Ranging over a non-positive integer executes the block zero times.

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