Master Golang: Range

range iterates over elements in a variety of data structures. Let’s see how to use `range` with some of the data structures we’ve already learned.
	package main
	import "fmt"
	func main() {
Here we use `range` to sum the numbers in a slice. Arrays work like this too.	nums := []int{2, 3, 4} sum := 0 for _, num := range nums { sum += num } fmt.Println("sum:", sum)
`range` on arrays and slices provides both the index and value for each entry. Above we didn’t need the index, so we ignored it with the blank identifier `_`. Sometimes we actually want the indexes though.	for i, num := range nums { if num == 3 { fmt.Println("index:", i) } }
`range` on map iterates over key/value pairs.	kvs := map[string]string{"a": "apple", "b": "banana"} for k, v := range kvs { fmt.Printf("%s -> %s\n", k, v) }
`range` can also iterate over just the keys of a map.	for k := range kvs { fmt.Println("key:", k) }
`range` on strings iterates over Unicode code points. The first value is the starting byte index of the `rune` and the second the `rune` itself. See Strings and Runes for more details.	for i, c := range "go" { fmt.Println(i, c) } }

$ go run range.go
sum: 9
index: 1
a -> apple
b -> banana
key: a
key: b
0 103
1 111

Next example: Functions.