How to round to nearest int when casting float to int in go

Question

When casting float to int the decimal is discarded. What\'s a clean way to cast so that it rounds to the nearest whole number instead.

x := int(3.6) sho

Answer 1

You could use int(math.Round(f)) to round to the nearest whole number when converting a float to an int in Go. The decimal is also discarded when a float is set to a byte or a rune. Truncation doesn't happen when it's set to a string or a bool.

package main

import (
  . "fmt"
  . "math"
)

func main() {
  f := 3.6
  c := []interface{}{byte(f), f, int(Round(f)), rune(f), Sprintf("%.f", f), f != 0}
  checkType(c)
}
func checkType(s []interface{}) {
  for k, _ := range s {
     Printf("%T %v\n", s[k], s[k])
  }
}

Round returns the nearest integer, rounding half away from zero. See https://golang.org/pkg/math/#Round. See https://stackoverflow.com/a/61503758/12817546.

f := 3.6 truncates to “uint8 3”, f is “float64 3.6”, int(Round(f)) rounds up to “int 4”, rune(f) truncates to “int32 3”, Sprintf("%.f", f) is “string 3.6” and f != 0 outputs “bool true”.

Answer 2

int(f+0.5) will cause for it to round upwards if it's >= .5