围棋之旅 https://tour.golang.org/
练习:纵梁
使IPAddr
类型工具fmt.Stringer
将地址打印为
虚线四边形。
例如,IPAddr{1, 2, 3, 4}
应打印为"1.2.3.4
".
package main
import "fmt"
type IPAddr [4]byte
// TODO: Add a "String() string" method to IPAddr.
func main() {
addrs := map[string]IPAddr{
"loopback": {127, 0, 0, 1},
"googleDNS": {8, 8, 8, 8},
}
for n, a := range addrs {
fmt.Printf("%v: %v\n", n, a)
}
}
没有隐式转换[]string
to []interface {}
. See 转换 https://golang.org/ref/spec#Conversions in Go 编程语言规范 https://golang.org/ref/spec。您需要提供显式转换。例如,
package main
import "fmt"
type IPAddr [4]byte
// A "String() string" method for IPAddr.
func (a IPAddr) String() string {
return fmt.Sprintf("%d.%d.%d.%d", a[0], a[1], a[2], a[3])
}
func main() {
addrs := map[string]IPAddr{
"loopback": {127, 0, 0, 1},
"googleDNS": {8, 8, 8, 8},
}
for n, a := range addrs {
fmt.Printf("%v: %v\n", n, a)
}
}
Output:
loopback: 127.0.0.1
googleDNS: 8.8.8.8