strings.Index() Function in Golang With Examples

strings.Index() Function in Golang is used to get the first instance of a specified substring. If the substring is not found, then this method will return -1.

Syntax:

func Index(str, sbstr string) int

Here, str is the original string and sbstr is a string whose we want to find index value.

Example 1:

// Go program to illustrate the
// String Index() Function

package main

import (
    "fmt"
    "strings"
)

// Main function
func main() {

    // Creating and initializing the strings
    str1 := "Welcome to GeeksforGeeks"
    str2 := "My name is XYZ"

    // Displaying strings
    fmt.Println("String 1: ", str1)
    fmt.Println("String 2: ", str2)

    // Using Index() function
    res1 := strings.Index(str1, "Geeks")
    res2 := strings.Index(str2, "is")

    // Displaying the result
    fmt.Println("\nIndex values:")
    fmt.Println("Result 1: ", res1)
    fmt.Println("Result 2: ", res2)

}

Output:

String 1:  Welcome to GeeksforGeeks
String 2:  My name is XYZ

Index values:
Result 1:  11
Result 2:  8

Example 2:

// Go program to illustrate the
// String Index() Function

package main

import (
    "fmt"
    "strings"
)

// Main function
func main() {

    // Using Index() function
    res1 := strings.Index("GFG", "H")
    res2 := strings.Index("GeeksforGeeks", "for")

    // Displaying the result
    fmt.Println("Result 1: ", res1)
    fmt.Println("Result 2: ", res2)

}

Output:

Result 1:  -1
Result 2:  5