How to Concatenate Strings in Go

1. Introduction

Concatenation is a fundamental operation in string manipulation, where you combine two or more strings end-to-end to form a new string. In Go, strings can be concatenated in several ways, including using the plus operator, the fmt.Sprintf function, and the strings.Builder type for more efficient concatenation in loops. This post will explore these methods for concatenating strings in Go.


String concatenation in Go is the process of appending one string to another to create a single string. Since strings in Go are immutable, each concatenation operation creates a new string.

2. Program Steps

1. Concatenate two strings using the plus operator.

2. Concatenate multiple strings using the fmt.Sprintf function.

3. Use strings.Builder for efficient concatenation in a loop.

3. Code Program

package main

import (

func main() {
	// Step 1: Concatenate two strings using the plus operator
	hello := "Hello"
	world := "World"
	result := hello + ", " + world + "!"

	// Step 2: Concatenate multiple strings using fmt.Sprintf
	name := "Jane"
	greeting := fmt.Sprintf("%s, %s!", hello, name)

	// Step 3: Use strings.Builder for efficient concatenation in a loop
	var builder strings.Builder
	words := []string{"Go", "is", "an", "expressive", "language"}
	for _, word := range words {
		builder.WriteString(" ")
	sentence := builder.String()


Hello, World!
Hello, Jane!
Go is an expressive language


1. package main - The package declaration for the Go program.

2. import "fmt" and import "strings" - Importing packages needed for string formatting and building.

3. hello, world, name - Variables holding string values.

4. result - A string resulting from the concatenation of hello, , , world, and ! using the + operator.

5. greeting - A string constructed using fmt.Sprintf, which allows for formatted string concatenation.

6. strings.Builder - A type designed for efficiently building strings piece by piece. Its WriteString method is used to append each word followed by a space to the builder.

7. sentence - The complete string constructed by the strings.Builder, extracted using its String method.

8. The fmt.Println function calls print each concatenated string to the console.

9. The output shows the various methods of string concatenation and the resulting strings.