Go Output

Printing with fmt.Println

fmt.Println prints one or more values to the console, separates them with spaces, and adds a newline at the end automatically.

package main

import "fmt"

func main() {
    fmt.Println("Go", "makes", "printing", "easy")
}

Formatted Output with fmt.Printf

fmt.Printf lets you build a formatted string using verbs, special placeholders starting with %, and does not add a newline automatically. Common verbs include %s for strings, %d for integers, %f for floats, and %v for any value's default representation.

package main

import "fmt"

func main() {
    name := "Maria"
    age := 29
    fmt.Printf("%s is %d years old\n", name, age)
}

Building Strings with fmt.Sprintf

fmt.Sprintf works exactly like Printf, but instead of printing to the console it returns the formatted text as a string, which you can store in a variable and use later.

package main

import "fmt"

func main() {
    name := "Maria"
    age := 29
    summary := fmt.Sprintf("%s is %d years old", name, age)
    fmt.Println(summary)
}

• fmt.Print — writes values with no automatic spacing or newline
• fmt.Println — writes values separated by spaces, then a newline
• fmt.Printf — writes a formatted string using verbs, no automatic newline
• fmt.Sprintf — returns a formatted string instead of printing it
• fmt.Sprintln — returns values joined with spaces and a trailing newline