如何将概率添加到随机数生成器中

这是随机数发生器代码。

'Generate 3 random numbers' 
Dim rn As New Random 
Dim result1, result2, result3 As Integer 
result1 = rn.Next(1, 12) 
result2 = rn.Next(1, 12) 
result3 = rn.Next(1, 12)

所以这段代码会生成3个随机数并将它们保存到不同的变量中。我想要发生以下事情。

1 has a 20% chance of being selected 
2 has a 28% chance of being selected

值需要在1和12之间，并且我需要选择3号沿该线东西。

我发现this but it seems to be a little off topic?

难道这可用于我想要什么？

来源

2015-11-19 Oliver Ketley

制作一个包含100个项目的数组。将数值1分为数组中的20个点，数值2分为数组中的28个点，依此类推。然后选择一个随机数组索引。根据您的值和概率，您可以简化或调整阵列的大小。

或者，您可以只存储边界对（{1，20}，{2，48}，...），获取一个小于最高边界值的随机数，然后找到最小对的数字你的边界值大于或等于随机结果。这里有一个例子：

Private rnd As New Random() 
Public Function GetValue() As Integer 
    'max value is 100 
    Dim boundaries = { 
     {20, 48, 56, 60, 69, 74, 77, 82, 84, 88, 92, 100}, 
     { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12} 
    } 

    Dim r As Integer = rnd.Next(1, 101) 'upper range is exclusive 
    For i As Integer = 0 To boundaries.GetUpperBound(1) 
     If boundaries(0, i) >= r Then Return boundaries(1, i) 
    Next 
    Throw New Exception() 'code should not be able to get here 
End Function 

Dim result1 As Integer = GetValue() 
Dim result2 As Integer = GetValue() 
Dim result3 As Integer = GetValue()

来源

2015-11-19 19:58:09

真是个好主意，从来没有像那样看过它。但我不完全确定什么会工作，因为我想要它。只要确定随机值需要在1到12之间，我需要选择3个数字。 –

听起来很棒，也许可以工作。你有一段代码示例吗？我有点不确定该怎么做？ –

增加了一些代码 –

-2

我以前正在研究生成一个随机名称列表，模仿他美国国家人口基数;所需的数千个名字模仿了美国人口中的重复使用。为此，我需要一个名字列表以及Sur名称和它们的使用频率。因此，我从社会保障管理局获取种子数据，以获得1000个First和Sur名称，以及它们的使用频率。

Think of three columns. The first column is a list of names, the second their frequency seen in the population bases, and the third is the rolling totals of their frequency added row to row: 

Marry, 57, 10 
John, 40, 60 
Lloyd, 2, 62 
Zac, 1, 61 

Read a seed file of any size into an area, along with the weight value for each name (or number). This script assigns the rolling total weight values, then generates a random number between 1 and the sum of all weights. Checks that random number against the rolling sum of weights to locate the number associated with that weight. 

Looking at the above example you have a 57% chance to generate Marry, and a 1% chance to generate Zac. 

The below script is a more robust example of the general idea. It will generate random numbers between 1 – 25, based on the probability of their weights. The portion of the script that generates the random numbers between 1 – 25 loops 128 times to give you 128 numbers based on their probability of being selected. 

I basically used something like this to generate thousands of random names to mimic a population bases that mirrored the USA. 


Dim iVar001, iVar002, iVar003 
Dim iMin, iMax, iRand, iRandN 
Dim iRow, iCol 
Dim aName 
Dim aList() 

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 
' iMin is the lower range of random numbers, iMax is the upper 
' range of random numbers being generated 
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 

iMin = 1 
iMax = 25 

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 
' Create a dinamic sized 2D area used to generate a random number 
' based on weighted Probability. Array values array(0, 0) threw 
' array(x, 0), where “x” is the upper range value of the number 
' to be generated, contains the range of random numbers you will 
' be generating. Array values array(0, 1) to array(x, 1) contains 
' the weight value for each number. Array values array(0,2) to 
' array(x,2) contains the rolling sun of the weight values. 
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 


ReDim aList(iMax - 1, 2) 
iVar001 = 0 
Do While iVar001 <= (iMax - 1) 
    Randomize 
    aList(iVar001, 0) = iVar001 + 1 
    aList(iVar001, 1) = Int(((20 * iMax) - iMin + 1)* Rnd + iMin) 
    If iVar001 = 0 Then 
    aList(iVar001, 2) = aList(iVar001, 1) 
    Else 
    aList(iVar001, 2) = aList(iVar001, 1) + aList(iVar001 - 1, 2) 
    End If 
    aName = aName & aList(iVar001, 0) & " - " & aList(iVar001, 1) & _ 
      " - " & aList(iVar001, 2) & vbCrLf 
    iVar001 = iVar001 + 1 
Loop 

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 
' Generate a message box containing the array values. 
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 

MsgBox ("List of numbers," & vbCrLf& "weight values and" & _ 
     vbCrLf & "totals of weights." & vbCrLf & vbCrLf & aName) 


aName = "" 
iCount000 = 1 
iCount001 = 1 
iCol001 = 0 

''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 
' Generate a randon number between 1 and the total of weight 
' values. Then step threw the array values until the the random 
' value is nolonger less than or equal to the running wieght value, 
' and record the number associated with that running weight value. 
' The count of random =numbers generates is controled by the 
' following Do While iCount000 <= 198. 
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' '' 

Do While iCount000 <= 198 
    Randomize 
    iRand = Int((aList(UBound(aList,1),UBound(aList,2)) - iMin + 1)* Rnd + iMin) 
    iVar001 = 0 
    Do While iRand >= aList(iVar001, 2) 
    iVar001 = iVar001 + 1 
    iRandN = aList(iVar001, 0) 
    Loop 
    iCount000 = iCount000 + 1 

    If iCount001 = "19" Then 
     aName = vbCrLf & aName 
     iCount001 = 0 
    Else 
     iCount001 = iCount001 + 1 
    End If 

    aName = iRandN & ", " & aName 
Loop 
MsgBox "List of random numbers in range " & iMin & " to " & iMax & "," & vbCrLf & _ 
     "based on weighted probability." & vbCrLf & vbCrLf & aName

来源

2016-09-07 18:37:12

如何将概率添加到随机数生成器中

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