One-liner to transform []int into string

Issue

Basically I have []int{1, 2, 3}, I want a one-liner that transforms this into the string “1, 2, 3” (I need the delimiter to be custom, sometimes ., sometimes ,, etc). Below is the best I could come up with. Searched online and did not seem to find a better answer.

In most languages there is in-built support for this, e.g.:

python:

> A = [1, 2, 3]
> ", ".join([str(a) for a in A])
'1, 2, 3'

go:

package main

import (
    "bytes"
    "fmt"
    "strconv"
)

// Could not find a one-liner that does this :(.
func arrayToString(A []int, delim string) string {

    var buffer bytes.Buffer
    for i := 0; i < len(A); i++ {
        buffer.WriteString(strconv.Itoa(A[i]))
        if i != len(A)-1 {
            buffer.WriteString(delim)
        }
    }

    return buffer.String()
}

func main() {
    A := []int{1, 2, 3}
    fmt.Println(arrayToString(A, ", "))
}

Surely there must be an utility buried into go that allows me to do this with a one-liner?

I know that there is strings.Join(A, ", "), but that only works if A is already []string.

Solution

To convert
A := []int{1, 2, 3, 4, 5, 6, 7, 8, 9}

to a one line delimited string like
“1,2,3,4,5,6,7,8,9”
use:

strings.Trim(strings.Join(strings.Fields(fmt.Sprint(A)), delim), "[]")

or:

strings.Trim(strings.Join(strings.Split(fmt.Sprint(A), " "), delim), "[]")

or:

strings.Trim(strings.Replace(fmt.Sprint(A), " ", delim, -1), "[]")

and return it from a function such as in this example:

package main

import "fmt"
import "strings"

func arrayToString(a []int, delim string) string {
    return strings.Trim(strings.Replace(fmt.Sprint(a), " ", delim, -1), "[]")
    //return strings.Trim(strings.Join(strings.Split(fmt.Sprint(a), " "), delim), "[]")
    //return strings.Trim(strings.Join(strings.Fields(fmt.Sprint(a)), delim), "[]")
}

func main() {
    A := []int{1, 2, 3, 4, 5, 6, 7, 8, 9}

    fmt.Println(arrayToString(A, ",")) //1,2,3,4,5,6,7,8,9
}

To include a space after the comma you could call arrayToString(A, ", ") or conversely define the return as return strings.Trim(strings.Replace(fmt.Sprint(a), " ", delim + " ", -1), "[]") to force its insertion after the delimiter.

Answered By – user6169399

Answer Checked By – Dawn Plyler (GoLangFix Volunteer)