vb.net - 如何从 Mathnet、vb.net 中的矩阵或向量中找到实体索引？

Question

假设我有一个矩阵 A=[1 2 3;4 5 6] 现在我想检查其中是否存在 5。答案应该是行和列，即 Row=1 Col=1 我试过 find 但没有发现它有用。

提前致谢

标签： vb.netmathnet-numerics

Answer 1

对于多维数组，我们的选择很糟糕。一种方法是循环数组以获取元素索引，或者尝试类似下面的代码，仅循环搜索的数字匹配。

ReadOnly matrix(,) As Integer = New Integer(1, 2) {{1, 2, 5}, {4, 5, 6}}

Structure GridData
    Dim Row As Integer
    Dim Col As Integer
End Structure


Function FindIndexesOfNumber(searchedNr As Integer) As List(Of GridData)


    Dim startIndex As Integer = 0
    Dim enumerator As List(Of GridData) = (From elements In matrix).ToList.Where(Function(x) x.Equals(searchedNr)).Select(Function(x)
                                                                                                                              'fake select, it's only for the loop which find numbers  
                                                                                                                              startIndex = Array.IndexOf(matrix.OfType(Of Integer)().ToArray(), searchedNr, startIndex + 1)
                                                                                                                              Dim matrixBound As Integer = matrix.GetUpperBound(1) + 1
                                                                                                                              Return New GridData With {
                                                                                                                               .Col = startIndex Mod matrixBound,
                                                                                                                               .Row = (startIndex \ matrixBound)
                                                                                                                               }
                                                                                                                          End Function).ToList





    For Each c In enumerator
        Console.WriteLine(String.Format("Col: {0} Row: {1}", c.Col.ToString, c.Row.ToString))
    Next

    Return enumerator

End Function

用法：

Dim indexes As List(Of GridData) = FindIndexesOfNumber(5)