How to compare two slices of bytes in Golang?

In Go, a slice is a powerful, flexible data structure that allows elements of the same type to be stored in a variable-length sequence. When working with byte slices ([]byte), Go provides easy-to-use functions in the bytes package to compare them. In this article we will learn "How to compare two slices of bytes in Golang".

Example

slice1 := []byte{'G', 'o', 'l', 'a', 'n', 'g'}
slice2 := []byte{'G', 'o', 'l', 'a', 'n', 'g'}
slice3 := []byte{'g', 'o', 'L', 'A', 'N', 'g'}

Syntax

func Compare(a, b []byte) int                                     #bytes.Compare()
func Equal(a, b []byte) bool                                         #bytes.Equal()
func DeepEqual(x, y interface{}) bool                      #reflect.DeepEqual()

Comparing with bytes.Compare()

The bytes.Compare function returns:

• 0 if the slices are equal,
• -1 if slice1 is less than slice2, and
• 1 if slice1 is greater than slice2.

Syntax

func Compare(a, b []byte) int

Example:

package main
import (
    "bytes"
    "fmt"
)

func main() {
    slice1 := []byte{'G', 'o', 'l', 'a', 'n', 'g'}
    slice2 := []byte{'G', 'o', 'l', 'a', 'n', 'g'}
    slice3 := []byte{'g', 'o', 'L', 'A', 'N', 'g'}

    fmt.Println(bytes.Compare(slice1, slice2)) // Output: 0 (equal)
    fmt.Println(bytes.Compare(slice1, slice3)) // Output: -1 (slice1 < slice3)
}

0
-1

Comparing with bytes.Equal()

To directly check if two byte slices are equal, use bytes.Equal, which returns true if the slices are identical.

Syntax

func Equal(a, b []byte) bool

Example

package main
import (
    "bytes"
    "fmt"
)
func main() {
    slc1 := []byte{'G', 'o', 'l', 'a', 'n', 'g'}
    slc2 := []byte{'G', 'o', 'l', 'a', 'n', 'g'}
    slc3 := []byte{'g', 'o', 'L', 'A', 'N', 'g'}

    fmt.Println(bytes.Equal(slc1, slc2)) // Output: true
    fmt.Println(bytes.Equal(slc1, slc3)) // Output: false
}

true
false

Using reflect.DeepEqual() (Alternative Method)

reflect.DeepEqual compares the values and structure of two variables. While not specific to byte slices, it can also be used for equality checks.

Syntax

func DeepEqual(x, y interface{}) bool

Example

package main
import (
    "fmt"
    "reflect"
)
func main() {
    slc1 := []byte{'G', 'o', 'l', 'a', 'n', 'g'}
    slc2 := []byte{'G', 'o', 'l', 'a', 'n', 'g'}
    slc3 := []byte{'g', 'o', 'L', 'A', 'N', 'g'}

    fmt.Println(reflect.DeepEqual(slc1, slc2)) // Output: true
    fmt.Println(reflect.DeepEqual(slc1, slc3)) // Output: false
}

true
false