How do you write multiline strings in Go?

Does Go have anything similar to Python's multiline strings:

<!-- language: lang-python -->

"""line 1
line 2
line 3"""

If not, what is the preferred way of writing strings spanning multiple lines?

According to the language specification, you can use a raw string literal, where the string is delimited by backticks instead of double quotes.

`line 1
line 2
line 3`

You can write:

"line 1" +
"line 2" +
"line 3"

which is the same as:

"line 1line 2line 3"

Unlike using back ticks, it will preserve escape characters. Note that the "+" must be on the 'leading' line - for instance, the following will generate an error:

"line 1"
+"line 2"

Use raw string literals for multi-line strings:

func main(){
    multiline := `line 
by line
and line
after line`
}

Raw string literals

> Raw string literals are character sequences between back quotes, as in `foo`. Within the quotes, any character may appear except back quote.

A significant part is that is raw literal not just multi-line and to be multi-line is not the only purpose of it.

> The value of a raw string literal is the string composed of the uninterpreted (implicitly UTF-8-encoded) characters between the quotes; in particular, backslashes have no special meaning...

So escapes will not be interpreted and new lines between ticks will be real new lines.

func main(){
    multiline := `line 
by line \n
and line \n
after line`

    // \n will be just printed. 
    // But new lines are there too.
    fmt.Print(multiline)
}

Concatenation

Possibly you have long line which you want to break and you don't need new lines in it. In this case you could use string concatenation.

func main(){
    multiline := "line " +
            "by line " +
            "and line " +
            "after line"

    fmt.Print(multiline) // No new lines here
}

Since " " is interpreted string literal escapes will be interpreted.

func main(){
    multiline := "line " +
            "by line \n" +
            "and line \n" +
            "after line"

    fmt.Print(multiline) // New lines as interpreted \n
}

From String literals:

• raw string literal supports multiline (but escaped characters aren't interpreted)
• interpreted string literal interpret escaped characters, like '\n'.

But, if your multi-line string has to include a backquote (`), then you will have to use an interpreted string literal:

`line one
  line two ` +
"`" + `line three
line four`

You cannot directly put a backquote (`) in a raw string literal (`xx`).
You have to use (as explained in "how to put a backquote in a backquoted string?"):

 + "`" + ...

Go and multiline strings

Using back ticks you can have multiline strings:

package main

import "fmt"

func main() {

	message := `This is a 
Multi-line Text String
Because it uses the raw-string back ticks 
instead of quotes.
`

	fmt.Printf("%s", message)
}

Instead of using either the double quote (“) or single quote symbols (‘), instead use back-ticks to define the start and end of the string. You can then wrap it across lines.

> If you indent the string though, remember that the white space will
> count.

Please check the playground and do experiments with it.

Creating a multiline string in Go is actually incredibly easy. Simply use the backtick (`) character when declaring or assigning your string value.

package main

import (
	"fmt"
)

func main() {
    // String in multiple lines
	str := `This is a
multiline
string.`
	fmt.Println(str + "\n")
	
    // String in multiple lines with tab
	tabs := `This string
		will have
		tabs in it`
	fmt.Println(tabs)
}

You can put content with `` around it, like

var hi = `I am here,
hello,
`

You have to be very careful on formatting and line spacing in go, everything counts and here is a working sample, try it https://play.golang.org/p/c0zeXKYlmF

package main

import "fmt"

func main() {
	testLine := `This is a test line 1
This is a test line 2`
	fmt.Println(testLine)
}

you can use raw literals.
Example

s:=`stack
overflow`

For me, I need to use `^{grave accent/backquote} and just write a simple test

+ "`" + ...

is ugly and inconvenient

so I take a character^{for example: 🐬 U+1F42C} to replace it

a demo

myLongData := `line1
line2 🐬aaa🐬
line3
` // maybe you can use IDE to help you replace all ` to 🐬
myLongData = strings.ReplaceAll(myLongData, "🐬", "`")

Performance and Memory Evaluation

<code>+ "`"</code> v.s. <code>replaceAll(, "🐬", "`")</code>

package main

import (
	"strings"
	"testing"
)

func multilineNeedGraveWithReplaceAll() string {
	return strings.ReplaceAll(`line1
line2
line3 🐬aaa🐬`, "🐬", "`")
}

func multilineNeedGraveWithPlus() string {
	return `line1
line2
line3` + "`" + "aaa" + "`"
}

func BenchmarkMultilineWithReplaceAll(b *testing.B) {
	for i := 0; i < b.N; i++ {
		multilineNeedGraveWithReplaceAll()
	}
}

func BenchmarkMultilineWithPlus(b *testing.B) {
	for i := 0; i < b.N; i++ {
		multilineNeedGraveWithPlus()
	}
}

cmd
> go test -v -bench=. -run=none -benchmem　　　　see more testing.B

output

goos: windows
goarch: amd64
pkg: tutorial/test
cpu: Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz
BenchmarkMultilineWithReplaceAll
BenchmarkMultilineWithReplaceAll-8    12572316      89.95 ns/op   24 B/op  1 allocs/op
BenchmarkMultilineWithPlus
BenchmarkMultilineWithPlus-8          1000000000   0.2771 ns/op    0 B/op  0 allocs/op
PASS
ok      tutorial/test   7.566s

Yes, The <code>+ "`"</code> has a better performance than the other.

For me this is what I use if adding \n is not a problem.

fmt.Sprintf("Hello World\nHow are you doing today\nHope all is well with your go\nAnd code")

Else you can use the raw string

multiline := `Hello Brothers and sisters of the Code
              The grail needs us.
             `

I use the + with an empty first string. This allows a somehow readable format and it works for const.

const jql = "" +
	"cf[10705] = '%s' and " +
	"status = 10302 and " +
	"issuetype in (10002, 10400, 10500, 10501) and " +
	"project = 10000"