使用范围循环遍历地图，仅迭代一次

I need to only iterate over a loop once in my golang template, currently it is looping over all the keys but I want it to stop after a single iteration.

How can I do this?

{{range .Users}}
<div>
  {{.Name}}
</div>
{{end}}

instead of range, give index with an argument

{{index .Users 0}}
<div>
  {{.Name}}
</div>
{{end}}

Two solutions; either check that your index is 0 when looping:

{{range $index, $element := . }}{{if eq $index 0 -}}
Item: {{$element}}
{{end}}{{end -}}

Or you could define a "first" function that takes a slice and truncates it to length 1.

{{range first .}}
Item: {{.}}
{{end}}

Here's complete code that demonstrates both, which you can also try on the playground.

package main

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

var t = template.Must(template.New("x").Parse(
    "[{{range $index, $element := . }}{{if eq $index 0 -}}{{$element}}{{end}}{{end -}}]"))

var funcs = map[string]interface{}{
    "first": func(arg []string) []string {
        if len(arg) > 0 {
            return arg[:1]
        }
        return nil
    },
}

var t2 = template.Must(template.New("x").Funcs(funcs).Parse(
    "[{{range first . }}{{.}}{{end -}}]"))

func main() {
    tmpls := []*template.Template{t, t2}
    for i, t := range tmpls {
        fmt.Println("TEMPLATE", i)
        a := []string{"one", "two", "three"}
        for j := 0; j < len(a); j++ {
            fmt.Println("with input slice of length", j)
            t.Execute(os.Stdout, a[:j])
            fmt.Println()
        }
        fmt.Println()
    }
}