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Golang bytes.LastIndexAny() Function with Examples

Golang | bytes.LastIndexAny() Function: Here, we are going to learn about the LastIndexAny() function of the bytes package with its usages, syntax, and examples.
Submitted by IncludeHelp, on September 24, 2021

bytes.LastIndexAny()

The LastIndexAny() function is an inbuilt function of the bytes package which is used to get the byte index of the last occurrence in the given byte slice (s – interpreted as a sequence of UTF-8-encoded Unicode code points) of any of the Unicode code points in chars. It returns -1 if chars are empty or if there is no code point in common.

It accepts two parameters (s []byte, chars string) and returns the byte index of the last occurrence in s of any of the Unicode code points in chars.

Syntax:

func LastIndexAny(s []byte, chars string) int

Parameter(s):

• s : The byte slice in which we have to check any character from the string chars.
• chars : The string whose characters (any) are to be checked within the s.

Return Value:

The return type of the bytes.LastIndexAny() function is an int, it returns the byte index of the last occurrence in s of any of the Unicode code points in chars.

Example 1:

// Golang program to demonstrate the
// example of bytes.LastIndexAny() function

package main

import (
	"bytes"
	"fmt"
)

func main() {
	str := "Hello, world!"

	fmt.Println(bytes.LastIndexAny(
		[]byte(str), "Hello"))
	fmt.Println(bytes.LastIndexAny(
		[]byte(str), "l"))
	fmt.Println(bytes.LastIndexAny(
		[]byte(str), "Hi"))
	fmt.Println(bytes.LastIndexAny(
		[]byte(str), "xw"))
	fmt.Println(bytes.LastIndexAny(
		[]byte(str), "y"))
}

Output:

10
10
0
7
-1

Example 2:

// Golang program to demonstrate the
// example of bytes.LastIndexAny() function

package main

import (
	"bytes"
	"fmt"
)

func main() {
	var str string
	var sep string

	str = "Hi there!"
	sep = "!"

	result := bytes.LastIndexAny([]byte(str), sep)
	if result != -1 {
		fmt.Printf("Any chars of %q found at the last index %d in %q\n",
			sep, result, str)
	} else {
		fmt.Printf("Any chars of %q doest not found in %q\n",
			sep, str)
	}

	str = "Aspire to inspire before we expire."
	sep = "expire."

	result = bytes.LastIndexAny([]byte(str), sep)
	if result != -1 {
		fmt.Printf("Any chars of %q found at the last index %d in %q\n",
			sep, result, str)
	} else {
		fmt.Printf("Any chars of %q doest not found in %q\n",
			sep, str)
	}

	str = "Aspire to inspire before we expire."
	sep = "yz"

	result = bytes.LastIndexAny([]byte(str), sep)
	if result != -1 {
		fmt.Printf("Any chars of %q found at the last index %d in %q\n",
			sep, result, str)
	} else {
		fmt.Printf("Any chars of %q doest not found in %q\n",
			sep, str)
	}
}

Output:

Any chars of "!" found at the last index 8 in "Hi there!"
Any chars of "expire." found at the last index 34 in "Aspire to inspire before we expire."
Any chars of "yz" doest not found in "Aspire to inspire before we expire."

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