2 分钟阅读
将以下英文翻译为中文:
https://gohugo.io/functions/apply/
Given a map, array, or slice, apply
returns a new slice with a function applied over it.
apply COLLECTION FUNCTION [PARAM...]
apply
expects at least three parameters, depending on the function being applied.
"."
standing in for each element of the sequence the function is to be applied against.Here is an example of a content file with names:
as a front matter field:
content/example.md
=== “yaml”
``` yaml
---
names:
- Derek Perkins
- Joe Bergevin
- Tanner Linsley
title: Example
---
```
=== “toml”
``` toml
+++
names = ['Derek Perkins', 'Joe Bergevin', 'Tanner Linsley']
title = 'Example'
+++
```
=== “json”
``` json
{
"names": [
"Derek Perkins",
"Joe Bergevin",
"Tanner Linsley"
],
"title": "Example"
}
```
You can then use apply
as follows:
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Which will result in the following:
"derek-perkins", "joe-bergevin", "tanner-linsley"
This is roughly equivalent to using the following with range:
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However, it is not possible to provide the output of a range to the delimit
function, so you need to apply
it.
If you have post-tag-list.html
and post-tag-link.html
as partials, you could use the following snippets, respectively:
layouts/partials/post-tag-list.html
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layouts/partials/post-tag-link.html
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This works, but the complexity of post-tag-list.html
is fairly high. The Hugo template needs to perform special behavior for the case where there’s only one tag, and it has to treat the last tag as special. Additionally, the tag list will be rendered something like Tags: tag1 , tag2 , tag3
because of the way that the HTML is generated and then interpreted by a browser.
This first version of layouts/partials/post-tag-list.html
separates all of the operations for ease of reading. The combined and DRYer version is shown next:
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Now in the completed version, you can sort the tags, convert the tags to links with layouts/partials/post-tag-link.html
, chomp off stray newlines, and join the tags together in a delimited list for presentation. Here is an even DRYer version of the preceding example:
layouts/partials/post-tag-list.html
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apply
does not work when receiving the sequence as an argument through a pipeline.