按降序C#对字符串列表进行自然排序 [英] Natural Sorting of list of string in descending order C#

问题描述

我想问一下如何使用

I would like to ask how to sort a List<string> in descending order using the Natural Sort Comparer library.

我想问一下您是否有人使用过这个库 https://www.codeproject.com/Articles/22517/Natural-Sort-比较器 对List<string>进行排序?

I would like to ask if you someone have use this library https://www.codeproject.com/Articles/22517/Natural-Sort-Comparer to sort a List<string>?

这是升序的代码段

public List<string> contents = new List<string>{ "a,b,c,d,e,f" };
public void sorting()
{
   using (NaturalSortComparer comparer = new NaturalSortComparer())
   {
      contents.Sort(comparer);
   }
}

我可以使其按升序进行排序，但不能按降序进行排序.

I'm able to make it work to sort as ascending, but not descending.

有什么想法吗?

推荐答案

让我们实现一个简单的扩展方法 :

Let's implement a simple extension method:

  public static partial class ComparerExtensions {
    public static IComparer<T> Reverse<T>(this IComparer<T> comparer) {
      if (null == comparer)
        throw new ArgumentNullException(nameof(comparer));

      return Comparer<T>.Create((left, right) => comparer.Compare(right, left));
    }
  }

然后，您可以反转任意一个任何比较器(ICompare<T>):

Then you can reverse any comparer (ICompare<T>) you like:

 MyList.Sort(YourCustomComparer.Reverse());

在您的情况下(比较器实现IDisposable有点奇怪的实现):

In your case (a bit strange implmentation with comparer implementing IDisposable):

 using (var naturalComparer = new NaturalComparer()) {
   contents.Sort(naturalComparer.Reverse()); 
 }

对于 C#4.0 或更早的版本(不具有Comparer<T>.Create)，我们可以实现以下扩展方法:

In case of C# 4.0 or earlier version (which doesn't have Comparer<T>.Create) we can implement the extension method like this:

  public static partial class ComparerExtensions {
    private sealed class ReversedComparer<T> : IComparer<T> {
      private readonly IComparer<T> m_Comparer;

      public ReversedComparer(IComparer<T> comparer) {
        m_Comparer = comparer;
      }

      public int Compare(T x, T y) {
        return m_Comparer.Compare(y, x);
      }
    }

    public static IComparer<T> Reverse<T>(this IComparer<T> comparer) {
      if (null == comparer)
        throw new ArgumentNullException(nameof(comparer));

      return new ReversedComparer<T>(comparer);
    }
  }

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