Go Rand套餐很难 [英] Difficulty with Go Rand package

问题描述

是否有Go函数在每次运行中返回真伪随机数？我的意思是，请考虑以下代码：

  package main 
 
 import（
 fmt
rand
）
 
 func main（）{
 fmt.Println（rand.Int31n（100））
} 
  

每次执行此代码时，我都会得到相同的输出。是否有一种方法会在每次调用它时返回不同的随机结果？ http://golang.org/pkg/randrel =noreferrer> rand 可用于生成基于特定初始值（称为种子）生成的伪随机数。 p>

这个初始种子的流行选择是例如当前时间（以纳秒为单位） - 当您多次执行程序时可能会有所不同。你可以用当前时间初始化随机生成器，像这样：

  rand.Seed（time.Now（）。UnixNano （））
  

（不要忘记导入 time ）还有另外一个叫做 crypto / rand ，它可以用来产生更好的随机值（这个生成器也可能带用户的鼠标移动，当前的热量的处理器和许多其他因素考虑在内）。但是，这个包中的函数要慢几倍，除非你不写一个pass-phrase生成器（或其他与安全有关的东西），否则正常的rand包可能没有问题。

Is there any Go function which returns true pseudo random number in every run? What I actually mean is, consider following code,

package main

import (
    "fmt"
    "rand"
)

func main() {
    fmt.Println(rand.Int31n(100))
}

Every time I execute this code, I get the same output. Is there a method that will return different, random results each time that it is called?

解决方案

The package rand can be used to generate pseudo random numbers, which are generated based on a specific initial value (called "seed").

A popular choice for this initial seed is for example the current time in nanoseconds - a value which will probably differ when you execute your program multiple times. You can initialize the random generator with the current time with something like this:

rand.Seed(time.Now().UnixNano())

(don't forget to import the time package for that)

There is also another package called crypto/rand which can be used to generate better random values (this generator might also take the user's mouse movements, the current heat of the processor and a lot of other factors into account). However, the functions in this package are several times slower and, unless you don't write a pass-phrase generator (or other security related stuff), the normal rand package is probably fine.

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