How to index characters in a Golang string?

Question

How to get an "E" output rather than 69?

package main

import "fmt"

func main() {
    fmt.Print("HELLO"[1])
}

Does Golang have function to convert a char to byte and vice versa?

Answer 1

Interpreted string literals are character sequences between double quotes "" using the (possibly multi-byte) UTF-8 encoding of individual characters. In UTF-8, ASCII characters are single-byte corresponding to the first 128 Unicode characters. Strings behave like slices of bytes. A rune is an integer value identifying a Unicode code point. Therefore,

package main

import "fmt"

func main() {
    fmt.Println(string("Hello"[1]))              // ASCII only
    fmt.Println(string([]rune("Hello, 世界")[1])) // UTF-8
    fmt.Println(string([]rune("Hello, 世界")[8])) // UTF-8
}

Output:

e
e
界

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Read:

Go Programming Language Specification section on Conversions.

The Go Blog: Strings, bytes, runes and characters in Go