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Golang bytes.IndexByte() Function with Examples

Golang | bytes.IndexByte() Function: Here, we are going to learn about the IndexByte() function of the bytes package with its usages, syntax, and examples.
Submitted by IncludeHelp, on September 23, 2021

bytes.IndexByte()

The IndexByte() function is an inbuilt function of the bytes package which is used to get the index of the first instance of the byte c in the byte slice b.

It accepts two parameters (b []byte, c byte) and returns the index of the first instance of c in b, or -1 if c is not present in b.

Syntax

func IndexByte(b []byte, c byte) int

Parameters

• b : The byte slice in which we have to check the byte.
• c : The byte value whose index of the first instance in the byte slice (b) is to be found.

Return Value

The return type of the bytes.IndexByte() function is an int, it returns the index of the first instance of c in b, or -1 if c is not present in b.

Example 1

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

package main

import (
	"bytes"
	"fmt"
)

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

	fmt.Println(bytes.IndexByte([]byte(str), 'H'))
	fmt.Println(bytes.IndexByte([]byte(str), 'l'))
	fmt.Println(bytes.IndexByte([]byte(str), 'e'))
	fmt.Println(bytes.IndexByte([]byte(str), 'x'))
	fmt.Println(bytes.IndexByte([]byte(str), 'y'))
}

Output:

0
2
1
-1
-1

Example 2

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

package main

import (
	"bytes"
	"fmt"
)

func main() {
	var str string
	var c byte

	str = "Hi there!"
	c = '!'

	result := bytes.IndexByte([]byte(str), c)
	if result != -1 {
		fmt.Printf("%c found at the IndexByte %d in %q\n",
			c, result, str)
	} else {
		fmt.Printf("%c doest not found in %q\n",
			c, str)
	}

	str = "Aspire to inspire before we expire."
	c = 't'

	result = bytes.IndexByte([]byte(str), c)
	if result != -1 {
		fmt.Printf("%c found at the IndexByte %d in %q\n",
			c, result, str)
	} else {
		fmt.Printf("%c doest not found in %q\n",
			c, str)
	}

	str = "Aspire to inspire before we expire."
	c = 'z'

	result = bytes.IndexByte([]byte(str), c)
	if result != -1 {
		fmt.Printf("%c found at the IndexByte %d in %q\n",
			c, result, str)
	} else {
		fmt.Printf("%c doest not found in %q\n",
			c, str)
	}
}

Output:

! found at the IndexByte 8 in "Hi there!"
t found at the IndexByte 7 in "Aspire to inspire before we expire."
z doest not found in "Aspire to inspire before we expire."

Golang bytes Package »

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