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-  Foxtable(狐表)  (http://foxtable.com/bbs/index.asp)
--  专家坐堂  (http://foxtable.com/bbs/list.asp?boardid=2)
----  关于排列组合问题  (http://foxtable.com/bbs/dispbbs.asp?boardid=2&id=185405)
--  作者：YDS
--  发布时间：2023/2/21 15:08:00
--  关于排列组合问题
列1 列2 列3 列4
A 1 X A1X
B 2 Y A1Y
C 3 A2X
D A2Y
E A3X
A3Y
B1X
B1Y
B2X
B2Y
B3X
B3Y
C1X
C1Y
C2X
C2Y
C3X
C3Y
D1X
D1Y
D2X
D2Y
D3X
D3Y
D1X
D1Y
D2X
D2Y
D3X
D3Y

\'上面表的排列组合代码如下：
Dim t1 As Date = Date.Now
Dim dt As DataTable = DataTables("表A")
Dim l1s As List(Of String) = dt.GetValues("列1", "列1 Is Not Null")
Dim l2s As List(Of String) = dt.GetValues("列2", "列2 Is Not Null")
Dim l3s As List(Of String) = dt.GetValues("列3", "列3 Is Not Null"）
dim jh as string
For Each l1 As String In l1s
     For Each l2 As String In l2s
           For Each l3 As String In l3s
                    jh = l1 & l2 & l3
           Next
    Next
Next
‘现在的问题是如果不确定有多少符合条件的列时代码如何写，如下表

列1 列2 列3 列4
A 1 A1
B 2 A2
C B1
B2
C1
C2


--  作者：有点蓝
--  发布时间：2023/2/21 15:50:00
--  
Dim lst As new List(Of String) 

Dim l1s As List(Of String) = dt.GetValues("列1", "列1 Is Not Null")
Dim l2s As List(Of String) = dt.GetValues("列2", "列2 Is Not Null")
if l2s.count > 0
for each s1 as string in l1s 
    for each s2 as string in l2s 
lst.add(s1 & s2)
    next
next
l1s.clear
l1s.addrange(lst)
lst.clear
end if
Dim l3s As List(Of String) = dt.GetValues("列3", "列3 Is Not Null"）
if l3s.count > 0
for each s1 as string in l1s 
    for each s3 as string in l3s
lst.add(s1 & s3)
    next
next
next
if l1s.count > 0 andalso lst.count = 0 then
lst.addrange(l1s)
end if

for each s as string in lst
output.show(s)
next