range

range COLLECTION

In Go templates, the falsy values are false, 0, any nil pointer or interface value, and any array, slice, map, or string of length zero. Everything else is truthy.

{{ $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.

This template will render the page title three times:

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

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.

See Go’s text/template documentation for more information.