Range

range 用于迭代各种各样的数据结构

    for i, c := range "go" {
        // c 是 unicode 码点(code point)，是 number
        fmt.Println(i, c,string(c))
    }

    nums := []int{2, 3, 4}
    sum := 0
    for i, num := range nums {
        sum += num

        if num == 3 {
            fmt.Println("index:", i)
        }
    }

    kvs := map[string]string{"a": "apple", "b": "banana"}
    for k, v := range kvs {
        fmt.Printf("%s -> %s\n", k, v)
    }