Coding Challenge: Create array from value in array of maps in frontmatter

Given the following frontmatter

date: 2016-03-14 21:21:41 +0000
author: Jim
  id: "a6"
  some_other_key: 2
  id: "a7"
  some_other_key: 3
  id: "a8"
  some_other_key: 23

How would I get an array of version ids? It needs to be an array variable (ex $ids) that can be passed to a partial or also output with the delimit function as so.

{{ delimit $ids ", " }}

// Outputs a6, a7, a8

I’ve tried everything I can come up with from the documentation, but can’t get anything to work.

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{{- range $i, $kw := .Params.versions -}}
  {{- if $i -}}, {{- end -}}
  {{ .id }}{{ .some_other_key }}
{{- end }}

It will only work if the .Params.versions is not taxonomy.


This is a bit of a hack, but one way would be to use the Scratch feature. Untested example:

{{ range $i, $v := .Params.versions }}
{{ with $ }}{{ $.Scratch.SetInMap "ids" . . }}{{ end }}
{{ end }}

{{ delimit ($.Scratch.GetSortedMapValues "ids") ", " }}

Thanks for the reply. I’m still getting my head around these Go Templates. Your solution works for printing what I need on the screen. Could you explain how this line works because it gives the desired result but I don’t understand why.

{{- if $i -}}, {{- end -}}

Scratch! Wow, I somehow overlooked that in the docs. That does exactly what I need and seems to work perfectly!

The numbering starts from zero, so during the first passing $i = 0. As a result, “if” condition is not executed and a comma is not added.

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