使用LINQ從屬性值中刪除項目使用LINQ

Question

我有一個順序的記錄列表。該簡化的結構如下：

Underline Text  Order 
-1  Header1 1 
-1  SubHeader1 2 
0   Data1  3 
-1  Header2 4 // this needs to be removed 
-1  SubHeader2 5 // this needs to be removed 
-1  Header3 6 
-1  SubHeader3 7 
0   Data3  8 
0   Data3a  9 

現在，由於沒有爲「頭2」無數據/「SubHeader2」對時，它需要被刪除。我可以這樣做For ...下一個循環查看「Order」列，並根據序列中當前的位置對+2項進行假設。有沒有辦法與LINQ做到這一點？

編輯：這是一個任意的頭對列表和至少一個或多個數據線。有時數據線丟失。需要刪除丟失數據行的「Header」/「SubHeader」對。

編輯2：這是我刪除不需要的標題對試圖緩解缺乏通過評論和投票工作的批評：

' Sorry for the VB listing. I thought the C# question tag would reach a wider audience 
Class SequentialObject 
    Public Property Underline As Integer 
    Public Property Text As String 
    Public Property Order As Integer 
End Class 

Shared Sub RemoveHeaderPairsWithNoDataLines() 
    Dim sequentialObjectsList As New List(Of SequentialObject) 
    Dim itemsToRemove As New List(Of SequentialObject) 

    sequentialObjectsList.Add(New SequentialObject With {.Underline = -1, .Text = "Header1", .Order = 1}) 
    sequentialObjectsList.Add(New SequentialObject With {.Underline = -1, .Text = "SubHeader1", .Order = 2}) 
    sequentialObjectsList.Add(New SequentialObject With {.Underline = 0, .Text = "Data1", .Order = 3}) 
    sequentialObjectsList.Add(New SequentialObject With {.Underline = -1, .Text = "Header2", .Order = 4}) 
    sequentialObjectsList.Add(New SequentialObject With {.Underline = -1, .Text = "SubHeader2", .Order = 5}) 
    sequentialObjectsList.Add(New SequentialObject With {.Underline = -1, .Text = "Header3", .Order = 6}) 
    sequentialObjectsList.Add(New SequentialObject With {.Underline = -1, .Text = "SubHeader3", .Order = 7}) 
    sequentialObjectsList.Add(New SequentialObject With {.Underline = 0, .Text = "Data3", .Order = 8}) 
    sequentialObjectsList.Add(New SequentialObject With {.Underline = 0, .Text = "Data3a", .Order = 9}) 

    For Each sequentialObject As SequentialObject In sequentialObjectsList 
     ' ignoring here the index out of bounds if current header/subheader are last in the list 
     Dim isUnderlinedTwoLinesAhead As Boolean = (sequentialObjectsList(sequentialObject.Order + 2).Underline = -1) 

     If isUnderlinedTwoLinesAhead Then 
      itemsToRemove.Add(sequentialObject) 
     End If 
    Next 

    For Each itemToRemove As SequentialObject In itemsToRemove 
     sequentialObjectsList.Remove(itemToRemove) 
    Next 

End Sub 

Answer 1

你可以嘗試這樣的事：

var exludeTextHashSet = new HashSet<string> { "Header2", "SubHeader2 " }; 
var result = records.Where(record=>!excludeHashSet.Contains(record.Text)) 
        .ToList(); 

本質您可以創建要刪除的記錄文本的查找，然後通過驗證將包含在結果列表中的每個記錄的文本值不會包含在中的文本值從初始記錄中過濾出來10。

Answer 2

我會使用Where刪除不需要的記錄，然後Select重新從頭開始重新計算正確的順序。

你如何確定這些記錄「沒有數據」？

Answer 3

我沒有完全理解這個問題，但好像你正在嘗試在一個有序列表上使用LINQ，這取決於列表的順序。 LINQ對此並不好，因爲它適用於無序的IEnumerables。我建議不要使用LINQ。

Answer 4

我會建議組織你的代碼更加面向對象。

public class Record 
{ 
    public int Underline { get; set; } 
    public string Text { get; set; } 
    public int Order { get; set; } 
} 

public class RecordGroup 
{ 
    public int Id { get; set; } 
    public Record Header { get; set; } 
    public Record SubHeader { get; set; } 
    public List<Record> DataList { get; set; } 
} 

---

這樣，檢索包含數據將是微不足道RecordGroup S：

List<RecordGroup> recordGroups = ... 

recordGroups.Where(g => g.DataList.Any()).OrderBy(g => g.Id);