Go – Find sub-byte in byte slice from last in go

bytes.LastIndexByte() function is used to find sub-byte in byte slice from last in go. It returns the index of sub-byte from last.

LastIndexByte() built-in function of bytes package returns the last instance of sub-byte in byte slice. It returns -1 if sub-byte is not present in byte slice.

bytes.LastIndexByte() function prototype:

func LastIndexByte(s []byte, c byte) int

Input parameters:
s: byte slices
c: byte to be searched in s from last.

Return:
It returns index of c byte in byte slice s from last.

Explanation on find sub-byte in byte slice from last in go

1)
s := []byte("He is all well and well")
c := byte('a')

Output: 19

2)
s = []byte("He is all well and well")
c = byte('z')

Output: -1

3)
s = []byte{10, 20, 30, 20, 30, 20, 40}
sep = byte(20)

Output: 5

Example:

package main

import (
	"bytes"
	"fmt"
)

// main function
func main() {
    
    s := []byte("He is all well and well")
    c := byte('a')
    
	fmt.Println(bytes.LastIndexByte(s, c))
	
	
    s = []byte("He is all well and well")
    c = byte('z')
    
    fmt.Println(bytes.LastIndexByte(s, c))
    

	s = []byte{10, 20, 30, 20, 30, 20, 40}
    c = byte(20)
    
    fmt.Println(bytes.LastIndexByte(s, c))
}

Output:

15
-1
5

To learn more about golang, Please refer given below link:

References:

https://golang.org/doc/