'How to convert from []byte to int in Go Programming

I need to create a client-server example over TCP. In the client side I read 2 numbers and I send them to the server. The problem I faced is that I can't convert from []byte to int, because the communication accept only data of type []byte.

Is there any way to convert []byte to int or I can send int to the server?

Some sample code will be really appreciated.

Thanks.

Solution 1:^[1]

You can use encoding/binary's ByteOrder to do this for 16, 32, 64 bit types

Play

package main

import "fmt"
import "encoding/binary"

func main() {
    var mySlice = []byte{244, 244, 244, 244, 244, 244, 244, 244}
    data := binary.BigEndian.Uint64(mySlice)
    fmt.Println(data)
}

Solution 2:^[2]

If []byte is ASCII byte numbers then first convert the []byte to string and use the strconv package Atoi method which convert string to int.

package main
import (
    "fmt"
    "strconv"
)

func main() {
    byteNumber := []byte("14")
    byteToInt, _ := strconv.Atoi(string(byteNumber))
    fmt.Println(byteToInt)
}

go playground - https://play.golang.org/p/gEzxva8-BGP

Solution 3:^[3]

Starting from a byte array you can use the binary package to do the conversions.

For example if you want to read ints :

buf := bytes.NewBuffer(b) // b is []byte
myfirstint, err := binary.ReadVarint(buf)
anotherint, err := binary.ReadVarint(buf)

The same package allows the reading of unsigned int or floats, with the desired byte orders, using the general Read function.

Solution 4:^[4]

now := []byte{0xFF,0xFF,0xFF,0xFF}
nowBuffer := bytes.NewReader(now)
var  nowVar uint32
binary.Read(nowBuffer,binary.BigEndian,&nowVar)
fmt.Println(nowVar)

4294967295

Solution 5:^[5]

For encoding/decoding numbers to/from byte sequences, there's the encoding/binary package. There are examples in the documentation: see the Examples section in the table of contents.

These encoding functions operate on io.Writer interfaces. The net.TCPConn type implements io.Writer, so you can write/read directly to network connections.

If you've got a Go program on either side of the connection, you may want to look at using encoding/gob. See the article "Gobs of data" for a walkthrough of using gob (skip to the bottom to see a self-contained example).

Solution 6:^[6]

The math/big provides a simple and easy way to convert a binary slice to a number playground

package main
import (
    "fmt"
    "math/big"
)
func main() {

    b := []byte{0x01, 0x00, 0x01}

    v := int(big.NewInt(0).SetBytes(b).Uint64())

    fmt.Printf("%v", v)
}

Solution 7:^[7]

binary.Read in encoding/binary provides mechanisms to convert byte arrays to datatypes.

Note that Network Byte Order is BigEndian, so in this case, you'll want to specify binary.BigEndian.

  package main

  import (
    "bytes"
    "encoding/binary"
    "fmt"
  )

  func main() {
    var myInt int
    b := []byte{0x18, 0x2d} // This could also be a stream
    buf := bytes.NewReader(b)
    err := binary.Read(buf, binary.BigEndian, &myInt) // Make sure you know if the data is LittleEndian or BigEndian
    if err != nil {
        fmt.Println("binary.Read failed:", err)
        return
    }
    fmt.Print(myInt)
  }

Reviewing this documentation may be helpful: https://pkg.go.dev/encoding/[email protected]#Read

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	blackgreen
Solution 2
Solution 3
Solution 4	Inasa Xia
Solution 5
Solution 6
Solution 7	Philip Constantinou

'How to convert from []byte to int in Go Programming

Solution 1:[1]

Solution 2:[2]

Solution 3:[3]

Solution 4:[4]

Solution 5:[5]

Solution 6:[6]

Solution 7:[7]