Convert fixed size array to variable sized array in Go

Question

I'm trying to convert a fixed size array [32]byte to variable sized array (slice) []byte:

package main

import (
        "fmt"
)

func main() {
        var a [32]byte
        b := []byte(a)
        fmt.Println(" %x", b)
}

but the compiler throws the error:

./test.go:9: cannot convert a (type [32]byte) to type []byte

How should I convert it?

Makpoc · Accepted Answer · 2015-01-20 13:51:56Z

43

Use b := a[:] to get the slice over the array you have. Also see this blog post for more information about arrays and slices.

answered Jan 20, 2015 at 13:51

Makpoc

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Comments

Ainar-G · Accepted Answer · 2015-01-20 13:51:55Z

20

There are no variable-sized arrays in Go, only slices. If you want to get a slice of the whole array, do this:

b := a[:] // Same as b := a[0:len(a)]

answered Jan 20, 2015 at 13:51

Ainar-G

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Note that slices behave a bit like variable-sized arrays in that, if you keep using append on a slice, it will grow by reallocation when necessary.