1

我正在尝试按存储的关键字对文章进行分类。我有一个类别的关键字列表，我希望为一篇文章分配一个关键字计数最多的类别。

For Each keyword As String In category.Keywords
    category.tempCount += Regex.Matches(article.Item("title").InnerXml, Regex.Escape(keyword)).Count
    category.tempCount += Regex.Matches(article.Item("description").InnerXml, Regex.Escape(keyword)).Count
Next

这是为每个类别完成的，为每篇文章运行。我正在尝试对列表进行排序，以判断哪个类别最适合本文。然而，最好的类别可能不止一个，而且没有一个类别适合。所以运行这个对我没有帮助：

Categories.Sort(
Function(article1 As ArticleCategory, article2 As ArticleCategory)
    Return article1.tempCount.CompareTo(article2.tempCount)
End Function)

也许我做这一切都是错的，但到目前为止，我认为我走在正确的道路上。（我在 Category 类中也有一个默认比较，它也不起作用。）

我在最可能导致的排序上遇到异常，因为它们不是唯一的。

我得到的异常是 InvalidOperationException：无法比较数组中的两个元素。那是使用我在 ArticleClass 中构建的比较器

Imports System.Xml

Class ArticleCategory
Implements IComparer(Of ArticleCategory)

Public ReadOnly key As Int32
Public ReadOnly Name As String
Public ReadOnly Keywords As List(Of String)
Public tempCount As Integer = 0

Public Sub New(ByVal category As XmlElement)
    key = System.Web.HttpUtility.UrlDecode(category.Item("ckey").InnerXml)
    Name = System.Web.HttpUtility.UrlDecode(category.Item("name").InnerXml)

    Dim tKeywords As Array = System.Web.HttpUtility.UrlDecode(category.Item("keywords").InnerXml).Split(",")
    Dim nKeywords As New List(Of String)
    For Each keyword As String In tKeywords
        If Not keyword.Trim = "" Then
            nKeywords.Add(keyword.Trim)
        End If
    Next

    Keywords = nKeywords
End Sub

'This should be removed if your using my solution.
Public Function Compare(ByVal x As ArticleCategory, ByVal y As ArticleCategory) As Integer Implements System.Collections.Generic.IComparer(Of ArticleCategory).Compare
    Return String.Compare(x.tempCount, y.tempCount)
End Function


End Class
4

2 回答 2

1

你需要实施IComparable而不是IComparer。

IComparer 将由执行排序的类（例如 List 类）实现，而 IComparable 将由被排序的类实现。

例如：

Public Function CompareTo(other As ArticleCategory) As Integer Implements System.IComparable(Of ArticleCategory).CompareTo
    Return Me.tempCount.CompareTo(other.tempCount)
End Function
于 2011-12-18T00:58:24.043 回答
1

我发现的最佳解决方案是使用 Microsoft LINQ（一种对象查询语言），它运行良好并且可以快速产生正确的结果。

Dim bestCat As ArticleCategory
bestCat = (From cat In Categories
           Order By cat.tempCount Descending, cat.Name
           Select cat).First

完成我的解决方案：

For Each category As ArticleCategory In Categories
    category.tempCount = 0

    For Each keyword As String In category.Keywords
        category.tempCount += Regex.Matches(System.Web.HttpUtility.UrlDecode(article.Item("title").InnerXml), Regex.Escape(keyword)).Count
        category.tempCount += Regex.Matches(System.Web.HttpUtility.UrlDecode(article.Item("description").InnerXml), Regex.Escape(keyword)).Count
    Next

Next

Dim bestCat As ArticleCategory

Try
    bestCat = (From cat In Categories
               Order By cat.tempCount Descending, cat.Name
               Select cat).First
Catch ex As Exception
    ReportStatus(ex.Message)
End Try

所以这是我对列表对象或数组进行排序或查询的首选方法。它可以在最快的时间内产生最好的结果，而无需将 IComparer 实现添加到您的类中。

在Microsoft.com上查看

于 2011-12-19T01:31:54.980 回答