主题：随机抽取的问题

请教老师，下面代码根据帮助上洗牌抽取，

 

想实现的是，例如，第一次随机抽取了其中的10行，第二次再随机抽取10行，但是第二次随机抽取的10行中包含第一次抽取中的5行

 

目前第一次抽取的行比较相邻排序，99,82，76,61,50,48,33,25,10 怎样能再分开一些，目前有1000多行

 

第一次       第二次

11              22

12              67

15              56

19              11

18              20

13              71

16              15

14              49

20              13

22              99

 

 

Dim cnt As Integer = DataTables("表C").DataRows.Count

Dim ids1 As New List(of Integer) '用于存储洗牌前的位置

Dim ids2 As New List(of Integer) '用于存储洗牌后的位置

For i As Integer = 0 To cnt -1 '准备初始的牌

    ids1.add(i)

Next

For i As Integer = 0 To cnt - 1 '开始洗牌

    ids2.Add(ids1(rand.Next(0,ids1.count)))

Next

Tables("表C").StopRedraw()

DataTables("表C").ReplaceFor("选择",False)

For i As Integer = 0 To 10 - 1 '10为要抽取的行数

    DataTables("表C").DataRows(ids2(i))("选择") = True

Next

Tables("表C").Filter = "[选择] = True"

Tables("表C").ResumeRedraw()

帮助文档洗牌有问题，换一种方式

 

http://www.foxtable.com/bbs/dispbbs.asp?BoardID=2&ID=86672&skin=0

 

你控制好洗牌次数（越多越好），就可以洗得很乱了；再有就是选取数据的时候，你不一定是从上往下选取10行嘛，选取数据的时候，你还能再随机选10个。

老师，第一个问题，output出来的行与“选择”出来的行不一样 ，output显示出来的数字是行号还是？？？

 

第二个问题，如何在第二次以后的洗牌与抽取中均包含上一次随机出现的50%的行，相当于第二次随机抽取的10行中包含上一次已经出现的5行

 

下面代码在命令窗口测试的  数据在表C

Dim dt As DataTable = DataTables("表C")
Dim cnt As Integer = dt.DataRows.Count
Dim ids(cnt - 1) As Integer
For i As Integer = 0 To cnt - 1
    ids(i) = i
Next
For i As Integer = 0 To cnt \ 3 '洗牌次数
    Dim id1 As Integer = rand.Next(100,cnt)
    Dim id2 As Integer = rand.Next(100,cnt)
    Dim vid As Integer = ids(id1)
    ids(id1) = ids(id2)
    ids(id2) = vid
Next
dt.StopRedraw()
DataTables("表C").ReplaceFor("选择",False)
For i As Integer = 300 To 309 '-1
    output.show(ids(i))
DataTables("表C").DataRows(ids(i))("选择") = True
Next
Tables("表C").Filter = "[选择] = True"
dt.ResumeRedraw()

 

 

下载信息  [文件大小：   下载次数： ]

点击浏览该文件:随机洗牌.table

1、ids存放的是行号，不是你的指标列的数据；

 

2、红色代码表示上次的行号，请自行用全局变量存放其值

 

Dim pids() As String = "1,3,5,9,10,12,20,15,16,17".split(",")

Dim dt As DataTable = DataTables("表C")
Dim cnt As Integer = dt.DataRows.Count
Dim ids(cnt - 1) As Integer
For i As Integer = 0 To cnt - 1
    ids(i) = i
Next
For i As Integer = 0 To cnt \ 3 '洗牌次数
    Dim id1 As Integer = rand.Next(100,cnt)
    Dim id2 As Integer = rand.Next(100,cnt)
    Dim vid As Integer = ids(id1)
    ids(id1) = ids(id2)
    ids(id2) = vid
Next
dt.StopRedraw()
DataTables("表C").ReplaceFor("选择",False)
Dim count As Integer = 0

Do While count < 5
    Dim rnd As Integer = Rand.Next(0, 10)
    If DataTables("表C").DataRows(pids(rnd))("选择") = False Then
        count += 1
        DataTables("表C").DataRows(pids(rnd))("选择") = True
    End If
Loop

Do While count < 10
    Dim rnd As Integer = Rand.Next(0, cnt)
    If DataTables("表C").DataRows(ids(rnd))("选择") = False Then
        count += 1
        DataTables("表C").DataRows(ids(rnd))("选择") = True
    End If
Loop
Tables("表C").Filter = "[选择] = True"
dt.ResumeRedraw()

 

老师，我对全局代码不是很熟悉，我在全局代码中这样写对吗 还是写VAR

 

Public pids() As String = "1,3,5,9,10,12,20,15,16,17".split(",")

 

另外，这段代码的是存原来5行的内容，是吗，如果上面的代码调整为抽取20行，是否在"1,3,5,9,10,12,20,15,16,17"，任意添加行号就可以了

Do While count < 5 '改成10也抽取10行，另外<10 的那段代码，改成5也是5行？？？？
    Dim rnd As Integer = Rand.Next(0, 10)
    If DataTables("表C").DataRows(pids(rnd))("选择") = False Then
        count += 1
        DataTables("表C").DataRows(pids(rnd))("选择") = True
    End If
Loop

 

 

全局代码

 

public pstr As String = ""

 

按钮代码

 

Dim pids() As String = pstr.split(",")
Dim num As Integer = 20
pstr = ""

Dim dt As DataTable = DataTables("表C")
Dim cnt As Integer = dt.DataRows.Count
Dim ids(cnt - 1) As Integer
For i As Integer = 0 To cnt - 1
    ids(i) = i
Next
For i As Integer = 0 To cnt \ 3 '洗牌次数
    Dim id1 As Integer = rand.Next(0,cnt)
    Dim id2 As Integer = rand.Next(0,cnt)
    Dim vid As Integer = ids(id1)
    ids(id1) = ids(id2)
    ids(id2) = vid
Next
dt.StopRedraw()
DataTables("表C").ReplaceFor("选择",False)
Dim count As Integer = 0

If pids.length >= num / 2
    Do While count < num / 2
        Dim rnd As Integer = Rand.Next(0, pids.length)
        If DataTables("表C").DataRows(pids(rnd))("选择") = False Then
            count += 1
            DataTables("表C").DataRows(pids(rnd))("选择") = True
            pstr &= pids(rnd) & ","
        End If
    Loop
End If
Do While count < num
    Dim rnd As Integer = Rand.Next(0, cnt)
    If DataTables("表C").DataRows(ids(rnd))("选择") = False Then
        count += 1
        DataTables("表C").DataRows(ids(rnd))("选择") = True
        pstr &= ids(rnd) & ","
    End If
Loop
Tables("表C").Filter = "[选择] = True"
dt.ResumeRedraw()
pstr = pstr.trim(",")
msgbox(pstr)