如何用包含數字的字符串對列表進行排序？

Question

我有一個包含地址的列表。 對列表進行排序時，地址中的數字被認為是字符串，並且排序不正確。 我應該如何對列表進行升序排序？

 Dim sortme As List(Of data) = tempdata 'main list containing addresses as strings.
     sortme.Sort(Function(p1 As data, p2 As data) numorder(p1.Value).CompareTo(numorder(p2.Value)))

       Private Function numorder(ByVal str As String)
        Try
            Dim words() As String = str.Split(" "c) 'read string up to first space (for number)
            Return Convert.ToInt32(words(0))
        Catch ex As Exception
        End Try
    End Function

電流輸出示例：

1001 street name

103 street name

1021 street name

它應該是：

103 street name

1001 street name

1021 street name

Answer 1

想法是編寫您自己的比較器，它將首先考慮數字前綴，然后考慮字符串本身。 然后可以在任何地方使用此比較器，例如在LINQ OrderBy() 。 這里是c＃中的示例，請參見下面的完整VB.NET版本。

   public class StreetComparer : IComparer<string>
    {
        public int Compare(string x, string y)
        {
            int indexOfSpaceX = x.IndexOf(' ');
            string numericalPartX = x.Substring(0, indexOfSpaceX);

            int indexOfSpaceY = y.IndexOf(' ');
            string numericalPartY = y.Substring(0, indexOfSpaceY);

            int numberX;
            int numberY;

            if(!int.TryParse(numericalPartX, out numberX) ||
                !int.TryParse(numericalPartY, out numberY))
            {
                //Some code to handle the case where number is missing
                throw new ArgumentException();
            }

            if (numberX!=numberY)
            {
                return numberX-numberY;
            }

            string textPartX = x.Substring(indexOfSpaceX + 1);
            string textPartY = x.Substring(indexOfSpaceY + 1);

            return String.Compare(textPartX, textPartY, true, CultureInfo.CurrentCulture);

        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            var myStreets = new[] {"01 aaa", "02 bbb"};

            var result = myStreets.OrderBy(s => s, new StreetComparer());
        }
    }

現在，一個VB.NET版本完全適合您的用例，其中的List具有按屬性排序的類：

Public Class StreetComparer
    Implements IComparer(Of String)
    Public Function Compare(x As String, y As String) As Integer
        Dim indexOfSpaceX As Integer = x.IndexOf(" "C)
        Dim numericalPartX As String = x.Substring(0, indexOfSpaceX)

        Dim indexOfSpaceY As Integer = y.IndexOf(" "C)
        Dim numericalPartY As String = y.Substring(0, indexOfSpaceY)

        Dim numberX As Integer
        Dim numberY As Integer

        If Not Integer.TryParse(numericalPartX, numberX) OrElse Not Integer.TryParse(numericalPartY, numberY) Then
            'Some code to handle the case where number is missing
            Throw New ArgumentException()
        End If

        If numberX <> numberY Then
            Return numberX - numberY
        End If

        Dim textPartX As String = x.Substring(indexOfSpaceX + 1)
        Dim textPartY As String = x.Substring(indexOfSpaceY + 1)

        Return [String].Compare(textPartX, textPartY, True, CultureInfo.CurrentCulture)

    End Function
End Class

Public Class Person
    Public Property Value() As String
        Get
            Return m_Value
        End Get
        Set
            m_Value = Value
        End Set
    End Property
    Private m_Value As String

    Public Sub New(value__1 As String)
        Value = value__1
    End Sub
End Class

Class Program
    Private Shared Sub Main(args As String())
        Dim sortme As New List(Of Person)(New () {New Person("1001 street name"), New Person("103 street name"), New Person("1021 street name")})

        Dim result = sortme.OrderBy(Function(p) p.Value, New StreetComparer())

        For Each person As var In result
            Console.WriteLine(person.Value)
        Next
        Console.ReadKey()
    End Sub
End Class