round

README

Rounding

Why!? Because Go's math package doesn't include a Round() function.

All of the implementations I saw lacked unit tests or comments to make it easy to understand, so I made one and tested it.

There are two functions:

• ToEven
  • Default in Python 3 and C#
  • -3.5 = -4
  • -2.5 = -2
  • -1.5 = -2
  • 1.5 = 2
  • 2.5 = 2
  • 3.5 = 4
• AwayFromZero
  • Default in Python 2
  • -3.5 = -4
  • -2.5 = -3
  • -1.5 = -2
  • 1.5 = 2
  • 2.5 = 3
  • 3.5 = 4

How to use

go get github.com/a-h/round

import "github.com/a-h/round"

func main() {
    fmt.Println(round.ToEven(float64(-3.5), 0)) // -4
    fmt.Println(round.ToEven(float64(-2.5), 0)) // -2
    fmt.Println(round.ToEven(float64(-1.5), 0)) // -2
    fmt.Println(round.ToEven(float64(-1.49), 0)) // -1
}

Reference

Learn about Rounding Methods.

• https://www.mathsisfun.com/numbers/rounding-methods.html

Issue on Github asking for a float function.

• https://github.com/golang/go/issues/4594

Discussion on Go forum discussing how to Round, and not really reaching consensus.

• https://groups.google.com/forum/#!topic/golang-nuts/ITZV08gAugI/discussion

Documentation

Index

• func AwayFromZero(v float64, decimals int) float64
• func ToEven(v float64, decimals int) float64

Functions

func AwayFromZero

func AwayFromZero(v float64, decimals int) float64

AwayFromZero rounds numbers away from zero. Used in Python 2 (but not Python 3, which uses ToEven). -3.5 rounds to -4 -2.5 rounds to -3 -1.5 rounds to -2 1.5 rounds to 2 2.5 rounds to 3 3.5 rounds to 4

func ToEven

func ToEven(v float64, decimals int) float64

ToEven rounds to the nearest even number. Used in Python 3 (but not Python 2, which uses AwayFromZero). -3.5 rounds to -4 -2.5 rounds to -2 -1.5 rounds to -2 1.5 rounds to 2 2.5 rounds to 2 3.5 rounds to 4