Go语言中如何实现随机数生成

golang的随机数生成方案

import (

    crand "crypto/rand"

    "fmt"

    "math/big"

    "math/rand"

    "strings"

    "time"

)

伪随机，性能高，重复率高

  "math/rand"

// 生成指定位数的字符

func GenerateSubId(width int) string {

    var letterRunes = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")

    b := make([]rune, width)

    for i := range b {

        b[i] = letterRunes[rand.New(rand.NewSource(time.Now().UnixNano())).Intn(len(letterRunes))]

    }

    return string(b)

}

真随机，性能低，重复率低

  crand "crypto/rand"

// 生成指定位数的字符

func GenerateSubId2(width int) string {

    var letterRunes = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")

    b := make([]rune, width)

    for i := range b {

        r, _ := crand.Int(crand.Reader, big.NewInt(31))

        result := int(r.Int64())

        b[i] = letterRunes[result]

    }

    return string(b)

}