我想在 C# 中比较两个字典，键是 string，值是 int 列表。我假设两个字典在它们都具有相同的键时是相等的，并且对于每个键作为值的列表具有相同的整数(两者不一定以相同的顺序)。

我使用了 this 中的两个答案和 this相关问题，但都未能通过测试函数 DoesOrderKeysMatter 和 DoesOrderValuesMatter 的测试套件。

我的测试套件:

using System;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.Collections.Generic;
using System.Linq;


namespace UnitTestProject1
{
    [TestClass]
    public class ProvideReportTests
    {
        [TestMethod]
        public void AreSameDictionariesEqual()
        {
            // arrange
            Dictionary<string, List<int>> dict1 = new Dictionary<string, List<int>>();
            List<int> list1 = new List<int>();
            list1.Add(1);
            list1.Add(2);
            dict1.Add("a", list1);
            List<int> list2 = new List<int>();
            list2.Add(3);
            list2.Add(4);
            dict1.Add("b", list2);

            // act
            bool dictsAreEqual = false;
            dictsAreEqual = AreDictionariesEqual(dict1, dict1);

            // assert
            Assert.IsTrue(dictsAreEqual, "Dictionaries are not equal");

        }

        [TestMethod]
        public void AreDifferentDictionariesNotEqual()
        {
            // arrange
            Dictionary<string, List<int>> dict1 = new Dictionary<string, List<int>>();
            List<int> list1 = new List<int>();
            list1.Add(1);
            list1.Add(2);
            dict1.Add("a", list1);
            List<int> list2 = new List<int>();
            list2.Add(3);
            list2.Add(4);
            dict1.Add("b", list2);

            Dictionary<string, List<int>> dict2 = new Dictionary<string, List<int>>();

            // act
            bool dictsAreEqual = true;
            dictsAreEqual = AreDictionariesEqual(dict1, dict2);

            // assert
            Assert.IsFalse(dictsAreEqual, "Dictionaries are equal");

        }

        [TestMethod]
        public void DoesOrderKeysMatter()
        {
            // arrange
            Dictionary<string, List<int>> dict1 = new Dictionary<string, List<int>>();
            List<int> list1 = new List<int>();
            list1.Add(1);
            list1.Add(2);
            dict1.Add("a", list1);
            List<int> list2 = new List<int>();
            list2.Add(3);
            list2.Add(4);
            dict1.Add("b", list2);

            Dictionary<string, List<int>> dict2 = new Dictionary<string, List<int>>();
            List<int> list3 = new List<int>();
            list3.Add(3);
            list3.Add(4);
            dict2.Add("b", list3);
            List<int> list4 = new List<int>();
            list4.Add(1);
            list4.Add(2);
            dict2.Add("a", list4);

            // act
            bool dictsAreEqual = false;
            dictsAreEqual = AreDictionariesEqual(dict1, dict2);

            // assert
            Assert.IsTrue(dictsAreEqual, "Dictionaries are not equal");

        }

        [TestMethod]
        public void DoesOrderValuesMatter()
        {
            // arrange
            Dictionary<string, List<int>> dict1 = new Dictionary<string, List<int>>();
            List<int> list1 = new List<int>();
            list1.Add(1);
            list1.Add(2);
            dict1.Add("a", list1);
            List<int> list2 = new List<int>();
            list2.Add(3);
            list2.Add(4);
            dict1.Add("b", list2);

            Dictionary<string, List<int>> dict2 = new Dictionary<string, List<int>>();
            List<int> list3 = new List<int>();
            list3.Add(2);
            list3.Add(1);
            dict2.Add("a", list3);
            List<int> list4 = new List<int>();
            list4.Add(4);
            list4.Add(3);
            dict2.Add("b", list4);

            // act
            bool dictsAreEqual = false;
            dictsAreEqual = AreDictionariesEqual(dict1, dict2);

            // assert
            Assert.IsTrue(dictsAreEqual, "Dictionaries are not equal");

        }


        private bool AreDictionariesEqual(Dictionary<string, List<int>> dict1, Dictionary<string, List<int>> dict2)
        {
            return dict1.Keys.Count == dict2.Keys.Count &&
                   dict1.Keys.All(k => dict2.ContainsKey(k) && object.Equals(dict2[k], dict1[k]));

            // also fails:
            //    return dict1.OrderBy(kvp => kvp.Key).SequenceEqual(dict2.OrderBy(kvp => kvp.Key));
        }
    }
}

比较这些词典的正确方法是什么？还是我的(公认的笨拙的)TestSuite 有错误？

更新

我正在尝试将 Servy 的答案合并到我的测试套件中，如下所示，但我遇到了一些错误(在 Visual Studio 中用红色波浪线下划线):

`Equals 方法中的

• SetEquals 说:“不包含接受 Generic.List 类型的第一个参数的 SetEquals 的定义。

• 在 AreDictionariesEqual中，它说DictionaryComparer 是一种类型，但用作变量。`

  namespace UnitTestProject1
  {
      [TestClass]
      public class ProvideReportTests
      {
          [TestMethod]
          // ... same as above
  
  
  
          private bool AreDictionariesEqual(Dictionary<string, List<int>> dict1, Dictionary<string, List<int>> dict2)
          {
              DictionaryComparer<string, List<int>>(new ListComparer<int>() dc = new DictionaryComparer<string, List<int>>(new ListComparer<int>();
              return dc.Equals(dict1, dict2);
  
          }
  
      }
  
      public class DictionaryComparer<TKey, TValue> :
          IEqualityComparer<Dictionary<TKey, TValue>>
      {
          private IEqualityComparer<TValue> valueComparer;
          public DictionaryComparer(IEqualityComparer<TValue> valueComparer = null)
          {
              this.valueComparer = valueComparer ?? EqualityComparer<TValue>.Default;
          }
          public bool Equals(Dictionary<TKey, TValue> x, Dictionary<TKey, TValue> y)
          {
              if (x.Count != y.Count)
                  return false;
              if (x.Keys.Except(y.Keys).Any())
                  return false;
              if (y.Keys.Except(x.Keys).Any())
                  return false;
              foreach (var pair in x)
                  if (!valueComparer.Equals(pair.Value, y[pair.Key]))
                      return false;
              return true;
          }
  
          public int GetHashCode(Dictionary<TKey, TValue> obj)
          {
              throw new NotImplementedException();
          }
      }
  
      public class ListComparer<T> : IEqualityComparer<List<T>>
      {
          private IEqualityComparer<T> valueComparer;
          public ListComparer(IEqualityComparer<T> valueComparer = null)
          {
              this.valueComparer = valueComparer ?? EqualityComparer<T>.Default;
          }
  
          public bool Equals(List<T> x, List<T> y)
          {
              return x.SetEquals(y, valueComparer);
          }
  
          public int GetHashCode(List<T> obj)
          {
              throw new NotImplementedException();
          }
      }
  
      public static bool SetEquals<T>(this IEnumerable<T> first, IEnumerable<T> second, IEqualityComparer<T> comparer)
          {
              return new HashSet<T>(second, comparer ?? EqualityComparer<T>.Default)
                  .SetEquals(first);
          }
  
  }
  

最佳答案

所以首先我们需要一个字典的相等比较器。它需要确保它们具有匹配的键，如果匹配，则比较每个键的值:

public class DictionaryComparer<TKey, TValue> :
    IEqualityComparer<Dictionary<TKey, TValue>>
{
    private IEqualityComparer<TValue> valueComparer;
    public DictionaryComparer(IEqualityComparer<TValue> valueComparer = null)
    {
        this.valueComparer = valueComparer ?? EqualityComparer<TValue>.Default;
    }
    public bool Equals(Dictionary<TKey, TValue> x, Dictionary<TKey, TValue> y)
    {
        if (x.Count != y.Count)
            return false;
        if (x.Keys.Except(y.Keys).Any())
            return false;
        if (y.Keys.Except(x.Keys).Any())
            return false;
        foreach (var pair in x)
            if (!valueComparer.Equals(pair.Value, y[pair.Key]))
                return false;
        return true;
    }

    public int GetHashCode(Dictionary<TKey, TValue> obj)
    {
        throw new NotImplementedException();
    }
}

但这本身还不够。我们需要使用另一个自定义比较器来比较字典的值，而不是默认比较器，因为默认列表比较器不会查看列表的值:

public class ListComparer<T> : IEqualityComparer<List<T>>
{
    private IEqualityComparer<T> valueComparer;
    public ListComparer(IEqualityComparer<T> valueComparer = null)
    {
        this.valueComparer = valueComparer ?? EqualityComparer<T>.Default;
    }

    public bool Equals(List<T> x, List<T> y)
    {
        return x.SetEquals(y, valueComparer);
    }

    public int GetHashCode(List<T> obj)
    {
        throw new NotImplementedException();
    }
}

它使用以下扩展方法:

public static bool SetEquals<T>(this IEnumerable<T> first, IEnumerable<T> second,
    IEqualityComparer<T> comparer)
{
    return new HashSet<T>(second, comparer ?? EqualityComparer<T>.Default)
        .SetEquals(first);
}

现在我们可以简单地写:

new DictionaryComparer<string, List<int>>(new ListComparer<int>())
    .Equals(dict1, dict2);

关于c# - 比较两个字典是否相等，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/21758074/