比较2字典<字符串，字符串>实例

Question

我想比较两个Dictionary<string, string>实例的内容，而不管它们包含的项目的顺序如何。 SequenceEquals也比较了顺序，所以我先通过键命令字典，然后拨打SequenceEquals。

有没有一种方法可以用来代替SequenceEquals，它只会比较内容？

如果没有，这是做这件事的理想方式吗？

Dictionary<string, string> source = new Dictionary<string, string>(); 
Dictionary<string, string> target = new Dictionary<string, string>(); 

source["foo"] = "bar"; 
source["baz"] = "zed"; 
source["blah"] = null; 

target["baz"] = "zed"; 
target["blah"] = null; 
target["foo"] = "bar"; 

// sequenceEquals will be false 
var sequenceEqual = source.SequenceEqual(target); 
// contentsEqual will be true 
var contentsEqual = source.OrderBy(x => x.Key).SequenceEqual(target.OrderBy(x => x.Key)); 

Answer 1

var contentsEqual = source.DictionaryEqual(target); 

// ... 

public static bool DictionaryEqual<TKey, TValue>(
    this IDictionary<TKey, TValue> first, IDictionary<TKey, TValue> second) 
{ 
    return first.DictionaryEqual(second, null); 
} 

public static bool DictionaryEqual<TKey, TValue>(
    this IDictionary<TKey, TValue> first, IDictionary<TKey, TValue> second, 
    IEqualityComparer<TValue> valueComparer) 
{ 
    if (first == second) return true; 
    if ((first == null) || (second == null)) return false; 
    if (first.Count != second.Count) return false; 

    valueComparer = valueComparer ?? EqualityComparer<TValue>.Default; 

    foreach (var kvp in first) 
    { 
     TValue secondValue; 
     if (!second.TryGetValue(kvp.Key, out secondValue)) return false; 
     if (!valueComparer.Equals(kvp.Value, secondValue)) return false; 
    } 
    return true; 
} 

Answer 2

我不知道是否有一个现有的方法，但你可以使用以下（略去了空args来检查）

public static bool DictionaryEquals<TKey,TValue>(
    this Dictionary<TKey,TValue> left, 
    Dictionary<TKey,TValue> right) { 

    var comp = EqualityComparer<TValue>.Default; 
    if (left.Count != right.Count) { 
    return false; 
    } 
    foreach (var pair in left) { 
    TValue value; 
    if (!right.TryGetValue(pair.Key, out value) 
     || !comp.Equals(pair.Value, value)) { 
     return false; 
    } 
    } 
    return true; 
} 

这将是最好添加一个超载以允许定制EqualityComparer<TValue>。

Answer 3

这将检查是否从source所有Values存在target，忽略了Keys

var result = source.All(x => target.Any(y => x.Value == y.Value)); 

Answer 4

如果使用SortedDictionary你不会需要应用自己的排序，可以是更加容易的使用方法：

void Main() 
{ 
    var d1 = new Dictionary<string, string> 
    { 
     ["a"] = "Hi there!", 
     ["b"] = "asd", 
     ["c"] = "def" 
    }; 
    var d2 = new Dictionary<string, string> 
    { 
     ["b"] = "asd", 
     ["a"] = "Hi there!", 
     ["c"] = "def" 
    }; 

    var sortedDictionary1 = new SortedDictionary<string, string>(d1); 
    var sortedDictionary2 = new SortedDictionary<string, string>(d2); 

    if (sortedDictionary1.SequenceEqual(sortedDictionary2)) 
    { 
     Console.WriteLine("Match!"); 
    } 
    else 
    { 
     Console.WriteLine("Not match!"); 
    } 
}