how to convert bool to int8 in golang

Question

bitSet := true
var bitSetVar int8

How can I assign bitSet to bitSetVar as 1

I can do this:

if bitSet {
   bitSetVar = 1
} else {
   bitSetVar = 0
}

Is this the best way?

Answer 1

Because the zero value for a int8 is 0, the else branch is not necessary.

bitSet := true
var bitSetVar int8
if bitSet {
   bitSetVar = 1
}

There are no conversions from bool to integer types. The if statement is the best you can do.

Answer 2

yes this is the best way (fast and optimized):

bitSet := true
bitSetVar := int8(0)
if bitSet {
    bitSetVar = 1
}

using var bitSetVar int8 or bitSetVar := int8(0) inside a function is the same, and you don't need else part, because the bitSetVar initialized with zero before that if statment.
while using if is OK (and fast) like this B2i function:

func B2i(b bool) int8 {
    if b {
        return 1
    }
    return 0
}

but you have another option using map too (not as fast as if, but nice and beautiful to show here):

var b2i = map[bool]int8{false: 0, true: 1}

like this working sample code (with commented outputs):

package main

import "fmt"

var b2i = map[bool]int8{false: 0, true: 1}

var i2b = []bool{false, true}

func B2i(b bool) int8 {
    if b {
        return 1
    }
    return 0
}
func main() {
    fmt.Println(B2i(true))  // 1
    fmt.Println(B2i(false)) // 0

    fmt.Println(b2i[true])  // 1
    fmt.Println(b2i[false]) // 0

    fmt.Println(i2b[1]) // true
    fmt.Println(i2b[0]) // false
}

Answer 3

Your way currently is the best, because it's fast, with the same way you can convert int8 to bool, even easier. Also you can save 1 line:

var bitSetVar int8
if bitSet {
   bitSetVar = 1
}

Go community had an issue to implement this conversion, but seems that not all people are agree.

Answer 4

In terms of memory efficiency, going by your approach of doing

if bitSet {
   bitSetVar = 1
} else {
   bitSetVar = 0
}

you are not using any extra variables to set your bitSetVar, hence I would say this is the best you could expect.

In terms of run-time, you are:

1. Checking the value of bitSet once, which is the least number of times you should be doing.

2. Setting the value of bitSetVar once, which you intend to do.

Till now, I would say you have been as efficient as you can be.

In terms of user readability, if you feel that this little snippet of code is making your code any less presentable, you could shift it into a function, maybe call it checkBitSetVar, like this:

func checkBitSetVar(mybool bool) int8{
    if mybool{
        return 1
    }
    return 0    //you just saved youself an else here!
}

and in the main, do:

setBitVar = checkBitSetVar(bitSet)

I think this is the best you can get out of Go.