Go – Get Index of Substring in String
To get the index of a substring in a string in Go programming, call Index
function of strings
package, and pass the string and substring as arguments to this function.
The syntax to get the index of the first occurrence of substring substr
in a string str
using strings.Index() is
strings.Index(str, substr)
where
strings
is the package.Index
is the function name.str
is the string in which we have to find the index ofsubstr
.
strings.Index() function returns an integer that represents the position of first occurrence of substr
in str
.
Examples
In the following program, we will take a string Welcome to Go Tutorial, Go Examples
and find the index of first occurrence of substring Go
.
example.go
package main
import (
"fmt"
"strings"
)
func main() {
var str = "Welcome to Go Tutorial, Go Examples"
var substr = "Go"
var index = strings.Index(str, substr)
fmt.Println("The index of substring in this string is: ", index)
}
Output
The index of substring in this string is: 11
If the substring is not present in the input string, strings.Index() returns -1
.
In the following program, we will take a string and substring such that substring is not present in the string. We will then use Index() to find the index of substring in given string. Since substring is not present in the string, Index() should return -1.
example.go
package main
import (
"fmt"
"strings"
)
func main() {
var str = "Welcome to Go Tutorial, Go Examples"
var substr = "Python"
var index = strings.Index(str, substr)
fmt.Println("The index of substring in this string is: ", index)
}
Output
The index of substring in this string is: -1
Conclusion
In this Golang Tutorial, we learned how to find the index of a substring in given string using strings.Index() function.