go-training/range.go at master · damindap/go-training

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package main

import "fmt"

// Range iterate over elements in a variety of data structures

func Range() {

// 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.

for i, c := range "go" {

fmt.Println(i, c)

}