go常用标准库功能

16进制编码

package main

import (
	"encoding/hex"
	"fmt"
)

func main() {
	bs := []byte{0x12, 0x34, 0xef}
	str := hex.EncodeToString(bs)
	bs2, _ := hex.DecodeString(str)
	fmt.Println(bs)
	fmt.Println(str)
	fmt.Println(bs2)
}

base64编码

package main

import (
	"encoding/base64"
	"fmt"
)

func main() {
	bs := []byte{0xff, 0xef, 0xff}
	str := base64.StdEncoding.EncodeToString(bs)
	strURL := base64.URLEncoding.EncodeToString(bs)
	bs2, _ := base64.StdEncoding.DecodeString(str)
	bs3, _ := base64.URLEncoding.DecodeString(strURL)
	fmt.Println(str)
	fmt.Println(strURL)
	fmt.Println(bs2)
	fmt.Println(bs3)
}

flag包设置命令行选项

package main

import (
	"flag"
	"fmt"
)

var n = flag.Bool("n", false, "print index")
var sep = flag.String("s", "|", "separator")

func main() {
	flag.Parse()
	if *n {
		for i, arg := range flag.Args() {
			fmt.Print(i, arg, *sep)
		}
	} else {
		for _, arg := range flag.Args() {
			fmt.Print(arg, *sep)
		}
	}
}