goslice

How to join a slice of strings into a single string?

package main

import (
"fmt"
"strings"
)

func main() {
reg := [...]string {"a","b","c"}
fmt.Println(strings.Join(reg,","))
}

gives me an error of:

prog.go:10: cannot use reg (type [3]string) as type []string in argument to strings.Join

Is there a more direct/better way than looping and adding to a var?

Solution

  • The title of your question is:

    How to join a slice of strings into a single string?

    but in fact, reg is not a slice, but a length-three array. [...]string is just syntactic sugar for (in this case) [3]string.

    To get an actual slice, you should write:

    reg := []string {"a","b","c"}

    (Try it out: https://play.golang.org/p/vqU5VtDilJ.)

    Incidentally, if you ever really do need to join an array of strings into a single string, you can get a slice from the array by adding [:], like so:

    fmt.Println(strings.Join(reg[:], ","))

    (Try it out: https://play.golang.org/p/zy8KyC8OTuJ.)