CODEWITHSUNDEEP
go
user_78361084
user_78361084

Reputation: 3898

How do I range a slice that's contained inside a slice of structs in a template?

I am trying to range over a couple of nested slices inside a template but get an error:

panic: template: abc:3: unexpected <range> in range

goroutine 1 [running]:
text/template.Must(...)
    /usr/local/go/src/text/template/helper.go:23
main.main()
    /tmp/sandbox748332064/main.go:38 +0x560

I've tried searching the docs but can't seem to figure out a workaround to being able to execute the code, even though is seems really simple.

My code:

package main

import (
    "log"
    "os"
    "text/template"
)

type Person struct {
    name     string
    children []string
}

func main() {
    p := []*Person{
      {
        name:     "Susy",
        children: []string{"Bob", "Herman", "Sherman"},
      },
      {
        name:     "Norman",
        children: []string{"Rachel", "Ross", "Chandler"},
      },
    }

    str := `
      {{$people := .}}
      {{range $i, $pp := range $people}}
        {{$children := $pp.children}}
        Name: {{$pp.name}}
        Children:
          {{range $j, $c := $children}}
          Child {{$j}}: {{$c}}
          {{end}}                   
      {{end}}
    `

    t := template.Must(template.New("abc").Parse(str))
    err := t.Execute(os.Stdout, p)
    if err != nil {
      log.Println(err)
    }

}

my playground

Upvotes: 0

Views: 246

Answers (1)

Thundercat
Thundercat

Reputation: 120941

Use this syntax for range:

  {{range $i, $pp := $people}}
    {{$children := $pp.Children}}
    Name: {{$pp.Name}}
    Children:
      {{range $j, $c := $children}}
      Child {{$j}}: {{$c}}
      {{end}}                   
  {{end}}

Also, export the struct fields so the fields can be used by the template. Use those exported names in the template.

Run it in the playground

Upvotes: 4

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