To find the index of a string in a Go, you can use the “Strings.Index()” method. The Strings.Index() is a built-in Go function that returns the index of the first instance of a substring in a given string. If the substring is unavailable in the given string, it returns -1.
Syntax
func Index(str, substring string) int
Parameters
- str: It is an initially provided string
- substring – It is the string whose Index value we need to find
Example 1
package main
import (
"fmt"
"strings"
)
// Main function
func main() {
// Initializing the Strings
text := "Go is an open-source programming language created at Google."
// Display the Strings
fmt.Println("Given String:", text)
// Using the Index Function
result1 := strings.Index(text, "open-source")
result2 := strings.Index(text, "Python")
// Display the Index Output
fmt.Println("Index of 'open-source' in the Given String:", result1)
fmt.Println("Index of 'Python' in the Given String:", result2)
// Using the Count Function
count1 := strings.Count(text, "o")
count2 := strings.Count(text, "Go")
// Display the Count Output
fmt.Println("Number of 'o' occurrences in the Given String:", count1)
fmt.Println("Number of 'Go' occurrences in the Given String:", count2)
}
Output
Given String: Go is an open-source programming language created at Google.
Index of 'open-source' in the Given String: 9
Index of 'Python' in the Given String: -1
Number of 'o' occurrences in the Given String: 6
Number of 'Go' occurrences in the Given String: 2
In this code example, we use the strings.Index() function to find the index of the first occurrence of the specified substrings within the given string. If the substring is not found, the function returns -1.
We also used the strings.Count() function to count the occurrences of the specified substrings within the given string.
Example 2
package main
import (
"fmt"
"strings"
)
func main() {
// Initializing the Strings
s1 := "Go is a powerful language"
s2 := "Golang is fun"
// Display the Strings
fmt.Println("First String:", s1)
fmt.Println("Second String:", s2)
// Using the Index Function
output1 := strings.Index(s1, "powerful")
output2 := strings.Index(s2, "fun")
// Display the Index Output
fmt.Println("Index of 'powerful' in the 1st String:", output1)
fmt.Println("Index of 'fun' in the 2nd String:", output2)
}
Output
First String: Go is a powerful language
Second String: Golang is fun
Index of 'powerful' in the 1st String: 8
Index of 'fun' in the 2nd String: 10
In this example, we used the “strings.Index()” function to find the index of the first occurrence of the specified substrings within the given strings. If the substring is not found, the function returns -1.

Krunal Lathiya is a Software Engineer with over eight years of experience. He has developed a strong foundation in computer science principles and a passion for problem-solving. In addition, Krunal has excellent knowledge of Distributed and cloud computing and is an expert in Go Language.