Golang: String

By Xah Lee. Date: 2018-08-13. Last updated: 2020-12-24.

Intepreted String Literal

String syntax is like this:

"abc"

package main

import "fmt"

func main() {

	var x = "abc and ♥"

	fmt.Println(x)
	// abc and ♥
}

String can contain Unicode character, example: ♥ (U+2665: BLACK HEART SUIT)

Any character can appear between the "double quotes", except the quote itself or newline character.

To include newline, use \n.

To include a quote character, use \", example: "the \"thing\""

Backslash Escapes

Golang: String Backslash Escape

Raw String Literal

If you don't want backslash to have special meaning, use ` (U+60: GRAVE ACCENT) to quote the string.

var x = `long text`

Anything can appear inside except the grave accent char itself.

And, carriage return character (Unicode codepoint 13) in it is discarded. If you run the command line tool gofmt, it will remove carriage return.

package main

import "fmt"

var x = `long text
many lines
	tab too`

func main() {

	fmt.Printf("%v\n", x)
}

String is a Sequence of Bytes

Golang string is a sequence of bytes.
We normally think of string as a sequence of characters, but each character is stored as 1 to 4 bytes by UTF-8 encoding. [see Unicode Basics: Character Set, Encoding, UTF-8]
Go string can contain any Unicode character, but stored as bytes.
String can store any byte sequence, and can contain byte sequences that is not valid encoding of any character. You can create a string of any byte by using the hexadecimal escape \xhh. [see Golang: String Backslash Escape]

For example, character A has codepoint 65 in decimal , and 41 in hexadecimal. So, "A" and "\x41" creates the same string.

package main

import "fmt"

func main() {

	fmt.Printf("%v\n", "A" == "\x41") // true

}

String Index

s[n]: Returns the nth byte of string s.
Index start at 0.
The return value's type is byte. [see Golang: Basic Types]

package main

import "fmt"

func main() {

	var x = "abc"

	fmt.Printf("%#v\n", x[0]) // 0x61
	fmt.Printf("%#v\n", x[1]) // 0x62
	fmt.Printf("%#v\n", x[2]) // 0x63

}