Go by Example: Range

The range keyword is used in Go to iterate over elements in an array, slice, string, map, or channel.

Here’s an example of using range with an array:

package main

import "fmt"

func main() {
    a := [3]int{1, 2, 3}
    for i, v := range a {
        fmt.Println(i, v)
    }
}

Output:

0 1
1 2
2 3

Here’s an example of using range with a slice:

package main

import "fmt"

func main() {
    a := []int{1, 2, 3}
    for i, v := range a {
        fmt.Println(i, v)
    }
}

Output:

0 1
1 2
2 3

Here’s an example of using range with a string:

package main

import "fmt"

func main() {
    a := "hello"
    for i, v := range a {
        fmt.Println(i, string(v))
    }
}

Output:

0 h
1 e
2 l
3 l
4 o

Here’s an example of using range with a map:

package main

import "fmt"

func main() {
    a := map[string]int{"foo": 42, "bar": 23}
    for k, v := range a {
        fmt.Println(k, v)
    }
}

Output:

bar 23
foo 42

The range keyword is a convenient and concise way to iterate over elements in Go, and is used extensively in many applications.