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How to find last index value of specified byte in slice of bytes in Golang?

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In Go language slice is more powerful, flexible, convenient than an array, and is a lightweight data structure. The slice is a variable-length sequence which stores elements of a similar type, you are not allowed to store different type of elements in the same slice.
In the Go slice of bytes, you can find the last index value of the specified byte in the given slice using LastIndexByte() function. This function returns the index of the last instance of the specified byte in the given slice of bytes. If the given byte is not available in the original slice, then this method will return -1. It is defined under the bytes package so, you have to import bytes package in your program for accessing LastIndexByte function.

Syntax:

func LastIndexByte(ori_slice []byte, val byte) int

Here, ori_slice is the original slice and val is a byte, whose we want to find the last index value. Let us discuss this concept with the help of the given examples:

Example 1:




// Go program to illustrate the concept of
// the last index in the slice of bytes
package main
  
import (
    "bytes"
    "fmt"
)
  
func main() {
  
    // Creating and finding the last
    // index of the slice of bytes
    // Using LastIndexByte function
    res1 := bytes.LastIndexByte([]byte("****Welcome to GeeksforGeeks****"),
                                                                 byte('G'))
      
    res2 := bytes.LastIndexByte([]byte("Learning how to trim a slice of bytes"), 
                                                                     byte('e'))
      
    res3 := bytes.LastIndexByte([]byte("GeeksforGeeks, Geek"), byte('x'))
  
    // Display the results
    fmt.Printf("Final Value:\n")
    fmt.Printf("\nSlice 1: %d", res1)
    fmt.Printf("\nSlice 2: %d", res2)
    fmt.Printf("\nSlice 3: %d", res3)
}


Output:

Final Value:

Slice 1: 23
Slice 2: 35
Slice 3: -1

Example 2:




// Go program to illustrate the concept of
// the last index in the slice of bytes
package main
  
import (
    "bytes"
    "fmt"
)
  
func main() {
  
    // Creating and initializing 
    // the slice of bytes
    // Using shorthand declaration
    slice_1 := []byte{'!', '!', 'G', 'e', 'e', 'k', 's'
      'f', 'o', 'r', 'G', 'e', 'e', 'k', 's', '#', '#'}
      
    slice_2 := []byte{'A', 'p', 'p', 'l', 'e'}
      
    slice_3 := []byte{'%', 'g', 'e', 'e', 'k', 's', '%'}
  
    // Displaying slices
    fmt.Printf("Original Slice:\n\n")
    fmt.Printf("Slice 1: %s", slice_1)
    fmt.Printf("\nSlice 2: %s", slice_2)
    fmt.Printf("\nSlice 3: %s", slice_3)
  
    // Finding the last index of the slice of 
    // bytes Using LastIndexByte function
    res1 := bytes.LastIndexByte(slice_1, byte('e'))
    res2 := bytes.LastIndexByte(slice_2, byte('p'))
    res3 := bytes.LastIndexByte(slice_3, byte('w'))
  
    // Display the results
    fmt.Printf("\n\nLast Index:\n")
    fmt.Printf("\nSlice 1: %d", res1)
    fmt.Printf("\nSlice 2: %d", res2)
    fmt.Printf("\nSlice 3: %d", res3)
  
}


Output:

Original Slice:

Slice 1: !!GeeksforGeeks##
Slice 2: Apple
Slice 3: %geeks%

Last Index:

Slice 1: 12
Slice 2: 2
Slice 3: -1


Last Updated : 26 Aug, 2019
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