How to get the last element in helm loop?

Question

values.yaml:

products:
  apples:
    - green
    - red
    - yellow

I want to convert this into JSON file in chart:

      "products": {
          "apples": [
            "green",
            "red",
            "yellow"
          ]
        },

In jinja2 it would look like something like this:

      "products": {
          "apples": [
{% for apple in products.apples%}
            "{{apple}}"{% if not loop.last %},{% endif %}
{% endfor %}
          ]
        },

In jinja2 loop.last is used. How it can be done in helm?

Answer 1

The easiest answer to your real question is to use the Helm toJson function.

"products": {
{{ toPrettyJson .Values.products | indent 2 }}
}

To do this by hand: in the core Go text/template language, you can assign temporary variables as you loop over a structure with range. There's a two-variable form that receives both the index and the value. You can then compare the index with the length of the list.

"products": {
  "apples": {
{{- $last := sub (len .Values.products.apples) 1 }}
{{- $index, $apple := range .Values.products.apples }}
    {{ quote $apple }}{{ if ne $index $last }},{{ end }}
{{- end }}
  }
}