How to efficiently concatenate strings in Go?

Question

In Go, a string is a primitive type, which means it is read-only, and every manipulation of it will create a new string. So if I want to concatenate strings many times without knowing the length of the resulting string, what's the best way to do it? The naive way would be: s := "" for i := 0; i < 1000; i++ { s += getShortStringFromSomewhere() } return s but that does not seem very efficient.

Lex Hoffman · Accepted Answer

Note added in 2018 The best way is to use the bytes package. It has a Buffer type which implements io.Writer. package main import ( "bytes" "fmt" ) func main() { var buffer bytes.Buffer for i := 0; i < 1000; i++ { buffer.WriteString("a") } fmt.Println(buffer.String()) } This does it in O(n) time.

Chris Gregori · Answer

here is a library function in the strings package called Join: http://golang.org/pkg/strings/#Join A look at the code of Join shows a similar approach to Append function Kinopiko wrote: https://golang.org/src/strings/strings.go#L420 Usage: import ( "fmt"; "strings"; ) func main() { s := []string{"this", "is", "a", "joined", "string
"}; fmt.Printf(strings.Join(s, " ")); } $ ./test.bin this is a joined string

Go Language

Similar Questions

Embedding Structs in Go with pointer or with value, what is difference between them?

How to reverse an array in Go?

How to crate for loop of two variables in Go?

On a mission to build Next-Gen Community Platform for Developers

Facebook

Twitter

Linkedin

Instagram