Appending integer to a string by casting and using the concatenation operator

Question

I am trying to concatenate an integer with an existing string by casting and the appending using +. But it doesn't work.

package main

import (
    "fmt"
)

func main() {
    a := 4 
    b := "The value of a is "

    fmt.Println(b + string(a))
}

This prints a garbage character on go playground and nothing on the Unix terminal. What could be the reason for this? What is incorrect with this method?

Answer 1

From the Go language spec:

Converting a signed or unsigned integer value to a string type yields a string containing the UTF-8 representation of the integer.

In order to achieve the desired result, you need to convert your int to a string using a method like strconv.Itoa:

package main

import (
    "fmt"
    "strconv"
)

func main() {
    a := 4 
    b := "The value of a is "

    fmt.Println(b + strconv.Itoa(a))
}

Answer 2

Use fmt.Sprintf or Printf; no casting required:

fmt.Sprintf("%s%d",s,i)