String Formatting in Go

Posted by yhuang
Public (Editable by Users)

Go offers excellent support for string formatting in the printf tradition. Here are some examples of common string formatting tasks.

Go
Edit
package main

import (
    "fmt"
    "os"
)

type point struct {
    x, y int
}

func main() {
  
    // In these examples we use fmt.Printf to directly output the result on stdout.
    // If you wanted to create a string result to be used in a different way,
    // you can use fmt.Sprintf instead.

    p := point{1, 2}
    fmt.Printf("%v\n", p)

    fmt.Printf("%+v\n", p)

    fmt.Printf("%#v\n", p)

    fmt.Printf("%T\n", p)

    fmt.Printf("%t\n", true)

    fmt.Printf("%d\n", 123)

    fmt.Printf("%b\n", 14)

    fmt.Printf("%c\n", 33)

    fmt.Printf("%x\n", 456)

    fmt.Printf("%f\n", 78.9)

    fmt.Printf("%e\n", 123400000.0)
    fmt.Printf("%E\n", 123400000.0)

    fmt.Printf("%s\n", "\"string\"")

    fmt.Printf("%q\n", "\"string\"")

    fmt.Printf("%x\n", "hex this")

    fmt.Printf("%p\n", &p)

    fmt.Printf("|%6d|%6d|\n", 12, 345)

    fmt.Printf("|%6.2f|%6.2f|\n", 1.2, 3.45)

    fmt.Printf("|%-6.2f|%-6.2f|\n", 1.2, 3.45)

    fmt.Printf("|%6s|%6s|\n", "foo", "b")

    fmt.Printf("|%-6s|%-6s|\n", "foo", "b")

    s := fmt.Sprintf("a %s", "string")
    fmt.Println(s)

    fmt.Fprintf(os.Stderr, "an %s\n", "error")
}