Golang separating items with comma in template
I am trying to display a list of comma separated values, and don't want to display a comma after the last item (or the only item if there is only one).
My code so far:
Equipment:
{{$equipment := .Equipment}}
{{ range $index, $element := .Equipment}}
{{$element.Name}}
{{if lt $index ((len $equipment) -1)}}
,
{{end}}
{{end}}
The current output: Equipment: Mat , Dumbbell ,
How do I get rid of the trailing comma
A nice trick you can use is:
Equipment:
{{$equipment := .Equipment}}
{{ range $index, $element := .Equipment}}
{{if $index}},{{end}}
{{$element.Name}}
{{end}}
This works because the first index is 0
, which returns false
in the if
statement. So this code returns false
for the first index, and then places a comma in front of each following iteration. This results in a comma separated list without a leading or trailing comma.
Add a template function to do the work for you. strings.Join
is perfect for your use case.
Assuming tmpl
contains your templates, add the Join
function to your template:
tmpl = tmpl.Funcs(template.FuncMap{"StringsJoin": strings.Join})
Template:
Equipment:
{{ StringsJoin .Equipment ", " }}
Playground
Docs: https://golang.org/pkg/text/template/#FuncMap
Another way to skin the cat, if you can create a new type for the field.
type MyList []string
func (list MyList) Join() string {
return strings.Join(list, ", ")
}
Then you can use the function in the template like regular:
{{ .MyList.Join }}