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diff --git a/docs/content/en/functions/len.md b/docs/content/en/functions/len.md new file mode 100644 index 000000000..b8e380e49 --- /dev/null +++ b/docs/content/en/functions/len.md @@ -0,0 +1,60 @@ +--- +title: len +linktitle: len +description: Returns the length of a variable according to its type. +godocref: https://golang.org/pkg/builtin/#len +date: 2017-02-01 +publishdate: 2017-02-01 +lastmod: 2017-04-18 +categories: [functions] +keywords: [] +signature: ["len INPUT"] +workson: [lists,taxonomies,terms] +hugoversion: +relatedfuncs: [] +deprecated: false +toc: false +aliases: [] +--- + +`len` is a built-in function in Golang that returns the length of a variable according to its type. From the Golang documentation: + +> Array: the number of elements in v. +> +> Pointer to array: the number of elements in *v (even if v is nil). +> +> Slice, or map: the number of elements in v; if v is nil, len(v) is zero. +> +> String: the number of bytes in v. +> +> Channel: the number of elements queued (unread) in the channel buffer; if v is nil, len(v) is zero. + +`len` is also considered a [fundamental function for Hugo templating][]. + +## `len` Example 1: Longer Headings + +You may want to append a class to a heading according to the length of the string therein. The following templating checks to see if the title's length is greater than 80 characters and, if so, adds a `long-title` class to the `<h1>`: + +{{< code file="check-title-length.html" >}} +<header> + <h1{{if gt (len .Title) 80}} class="long-title"{{end}}>{{.Title}}</h1> +</header> +{{< /code >}} + +## `len` Example 2: Counting Pages with `where` + +The following templating uses [`where`][] in conjunction with `len` to figure out the total number of content pages in a `posts` [section][]: + +{{< code file="how-many-posts.html" >}} +{{ $posts := (where .Site.RegularPages "Section" "==" "post") }} +{{ $postCount := len $posts }} +{{< /code >}} + +Note the use of `.RegularPages`, a [site variable][] that counts all regular content pages but not the `_index.md` pages used to add front matter and content to [list templates][]. + + +[fundamental function for Hugo templating]: /templates/introduction/ +[list templates]: /templates/lists/ +[section]: /content-management/sections/ +[site variable]: /variables/site/ +[`where`]: /functions/where/
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