Last item in a template range
Given the template:
{{range $i, $e := .SomeField}}
{{if $i}}, {{end}}
$e.TheString
{{end}}
This can output:
one, two, three
If, however, I want to output:
one, two, and three
I'd need to know which is the last element in the range above.
I can set a variable that holds the length of the array .SomeField, but that will always be 3, and the $i value above will only ever get to 2. And you can't perform arithmetic in templates from what I've seen.
Is detecting the last value in a template range possible? Cheers.
Answer
This is probably not the most elegant solution but it's the best I could find:
http://play.golang.org/p/MT91mLqk1s
package main
import (
"os"
"reflect"
"text/template"
)
var fns = template.FuncMap{
"last": func(x int, a interface{}) bool {
return x == reflect.ValueOf(a).Len() - 1
},
}
func main() {
t := template.Must(template.New("abc").Funcs(fns).Parse(`{{range $i, $e := .}}{{if $i}}, {{end}}{{if last $i $}}and {{end}}{{$e}}{{end}}.`))
a := []string{"one", "two", "three"}
t.Execute(os.Stdout, a)
}
Note: You can also do it without reflect using the len function (credit to Russ Cox):
http://play.golang.org/p/V94BPN0uKD
c.f.