go生成不重复的纯数字6位的随机数

最近在学go, 按照入门指南学完go的基础语法, 开始学习go的标准库;  借用生成这个小任务复习一下go的基础语法.

推荐go编辑, jb公司的goland, 超级好用.

推荐go入门指南, https://tour.go-zh.org/list

package main

import (
    "fmt"
    "math/rand"
    "sync"
)

func main() {
    //fmt.Println("random: ", rand.Intn(100))
    res := Example(, )
    ; i<len(res); i++ {
        fmt.Println(i+,res[i])
    }
}

/**
len: 长度
max: 个数
随机生成长度为len的max个纯数字随机数
 */
func Example(length int, max int) []string{
    // Seeding with the same value results in the same random sequence each run.
    // For different numbers, seed with a different value, such as
    // time.Now().UnixNano(), which yields a constantly-changing number.
    //rand.Seed(42)

    digitNumber := []string {
        ",
        ",
        ",
        ",
        ",
        ",
        ",
        ",
        ",
        ",
    }
    // 用make创建map

    set := New()
    for ; set.Len() < max ;  {
        ranNumber := ""
        ; j<length; j++ {
            ranNumber += digitNumber[rand.Intn(len(digitNumber))]
        }
        if !set.Has(ranNumber){
            set.Add(ranNumber)
        }
    }

    return set.List()

}

/**
构造set类型
 */
type Set struct {
    m map[string]bool
    sync.RWMutex
}

func New() *Set {
    return &Set{
        m: map[string]bool{},
    }
}

func (s *Set) Add(item string) {
    s.Lock()
    defer s.Unlock()
    s.m[item] = true
}

func (s *Set) Remove(item string) {
    s.Lock()
    s.Unlock()
    delete(s.m, item)
}

func (s *Set) Has(item string) bool {
    s.RLock()
    defer s.RUnlock()
    _, ok := s.m[item]
    return ok
}

func (s *Set) Len() int {
    return len(s.List())
}

func (s *Set) Clear() {
    s.Lock()
    defer s.Unlock()
    s.m = map[string]bool{}
}

func (s *Set) IsEmpty() bool {
     {
        return true
    }
    return false
}

func (s *Set) List() []string {
    s.RLock()
    defer s.RUnlock()
    list := []string{}
    for item := range s.m {
        list = append(list, item)
    }
    return list
}