组合在列表

Question

（（的对象）列出的）我有一个动态列表（SuperList）与N个项目，例如在这里与三个项目A，B和C：

Dim A As New List(Of String) 
A.Add("Aa") 
A.Add("Bb") 
A.Add("Cc") 

Dim B As New List(Of String) 
B.Add("Small") 
B.Add("Large") 

Dim C As New List(Of Integer) 
C.Add(1) 
C.Add(2) 

Dim SuperList As New List(Of Object) 
SuperList.Add(A) 
SuperList.Add(B) 
SuperList.Add(C) 
... 

我需要从生成SuperList另一个List（Of List（Of String））：

Aa – Small – 1 
Aa – Small – 2 
Aa – Large – 1 
Aa – Large – 2 
Bb – Small – 1 
Bb – Small – 2 
Bb – Large – 1 
Bb – Large – 2 
Cc – Small – 1 
Cc – Small – 2 
Cc – Large – 1 
Cc – Large – 2 

SuperList中的项数是动态的。怎么做？

Answer 1

你基本上试图计算可变数量列表的笛卡尔乘积。

这MSDN article讨论的话题，并配备了下面的函数（C＃代码）

static IEnumerable<IEnumerable<T>> CartesianProduct<T>(this IEnumerable<IEnumerable<T>> sequences) 
{ 
    IEnumerable<IEnumerable<T>> emptyProduct = new[] { Enumerable.Empty<T>() }; 
    return sequences.Aggregate( 
    emptyProduct, 
    (accumulator, sequence) => 
     from accseq in accumulator 
     from item in sequence 
     select accseq.Concat(new[] {item})); 
} 

你会呼吁SuperList该功能。我坏在VB.NET，所以我通过automated converter

<System.Runtime.CompilerServices.Extension> _ 
Private Shared Function CartesianProduct(Of T)(sequences As IEnumerable(Of IEnumerable(Of T))) As IEnumerable(Of IEnumerable(Of T)) 
    Dim emptyProduct As IEnumerable(Of IEnumerable(Of T)) = New() {Enumerable.Empty(Of T)()} 
    Return sequences.Aggregate(emptyProduct, Function(accumulator, sequence) From accseq In accumulatorFrom item In sequenceaccseq.Concat(New() {item})) 
End Function 

跑的功能，请纠正我，如果这个“翻译”是错误的。