# formatting numbers

• If the numbers are converted to the string, they usually need to be reasonably formatted. The formatting of a number means the number is printed with a given number, made up of digits and decimals. The representation of a value can also be chosen. A closely related problem with this, however, is the localization of number formatting. For example, some languages use comma-separated zeros.

## Create the format.go file with the following content:

        package main

import (
"fmt"
)

var integer int64 = 32500
var floatNum float64 = 22000.456

func main() {

// Common way how to print the decimal
// number
fmt.Printf("%d \n", integer)

// Always show the sign
fmt.Printf("%+d \n", integer)

// Print in other base X -16, o-8, b -2, d - 10
fmt.Printf("%X \n", integer)
fmt.Printf("%#X \n", integer)

fmt.Printf("%010d \n", integer)

fmt.Printf("% 10d \n", integer)

fmt.Printf("% -10d \n", integer)

// Print floating
// point number
fmt.Printf("%f \n", floatNum)

// Floating-point number
// with limited precision = 5
fmt.Printf("%.5f \n", floatNum)

// Floating-point number
// in scientific notation
fmt.Printf("%e \n", floatNum)

// Floating-point number
// %e for large exponents
// or %f otherwise
fmt.Printf("%g \n", floatNum)

}



output:

sangam:golang-daily sangam$go run format.go 32500 +32500 7EF4 0X7EF4 0000032500 32500 32500 22000.456000 22000.45600 2.200046e+04 22000.456  ## Create the file localized.go with the following content:  package main import ( "golang.org/x/text/language" "golang.org/x/text/message" ) const num = 100000.5678 func main() { p := message.NewPrinter(language.English) p.Printf(" %.2f \n", num) p = message.NewPrinter(language.German) p.Printf(" %.2f \n", num) }  output: sangam:golang-daily sangam$ go run localized.go
100,000.57
100.000,57
sangam:golang-daily sangam\$



## How it works…

• The code example shows the most commonly used options for integers and floating-point numbers.
• Note:The formatting in Go is derived from C’s printf function. The so-called verbs are used to define the formatting of a number. The verb, for example, could be %X, which in fact is a placeholder for the value.
• Besides the basic formatting, there are also rules in formatting that are related to the local manners. With formatting, according to the locale, the package golang.org/x/text/message could help. See the second code example in this recipe. This way, it is possible to localize the number formatting.

## There’s more…

• For all formatting options, see the fmt package. The strconv package could also be useful in case you are looking to format numbers in a different base. The following recipe describes the possibility of number conversion, but as a side effect, the options of how to format numbers in a different base are presented