Question

我需要一些帮助来开发一种算法，该算法基于匹配的键/值对来合并列表列表。

在下面的示例中，我有3个List＆gt;我想使用Merge方法调用减少/合并的实例。 Merge的对象是获取包含任何匹配键/值对的实例，并将两个列表合并到包含两个列表中所有对的新列表中。因此，在此示例中，Merge方法应将3个列表压缩为1，因为list1和list2都包含匹配的键名和“key1”和“key2”的值。然后list1和list2的新合并列表将进一步与list3合并，因为它们都包含匹配的键名和“key4”的值。

任何人对高效算法都有任何想法？我目前正在使用一种非常慢的递归方法，因为它将每个列表与每个其他列表进行比较。

    var list1 = new List<KeyValuePair<string, string>> { 
        new KeyValuePair<string,string>("key1","2"), 
        new KeyValuePair<string,string>("key2","5"),
        new KeyValuePair<string,string>("key3","20")
    };

    var list2 = new List<KeyValuePair<string, string>> { 
        new KeyValuePair<string,string>("key1","2"), 
        new KeyValuePair<string,string>("key2","5"),
        new KeyValuePair<string,string>("key4","10"),
        new KeyValuePair<string,string>("key5","A"),
        new KeyValuePair<string,string>("key6","B"),
        new KeyValuePair<string,string>("key7","C")
    };

    var list3 = new List<KeyValuePair<string, string>> { 
        new KeyValuePair<string,string>("key10","2"), 
        new KeyValuePair<string,string>("key20","5"),
        new KeyValuePair<string,string>("key4","10"),
        new KeyValuePair<string,string>("key40","2")
    };

    var fullList = new List<IList<KeyValuePair<string, string>>>();

    fullList.Add(list1); 
    fullList.Add(list2); 
    fullList.Add(list3);

    List<IList<KeyValuePair<string, string>>> mergedList = fullList.Merge();

    /*
     output should be a single a single IList<KeyValuePair<string, string>> with a count of 10 KeyValuePair<string,string> items
     mergedList would contain the following key/value pairs

        "key1","2" 
        "key2","5"
        "key3","20"
        "key4","10"
        "key5","A"
        "key6","B"
        "key7","C"
        "key10","2" 
        "key20","5"
        "key40","2"
    */

Answer 1

请参阅linq set operators http://geekswithblogs.net/BlackRabbitCoder/archive/2011/05/05/c.net-little-wonders-the-linq-set-operations----theyre-not.aspx

上的这篇文章

Answer 2

看起来您可以使用Dictionary<String, HashSet<String>>来存储合并的数据。这将允许您快速查找输出是否已包含所需的键，如果不是，则添加它（并且，对于它的值，包含当前项的值的哈希集）。如果密钥已经存在于字典中，只需获取值（一个哈希集）并调用它的Add方法，该方法已经有效地防止了重复。

Answer 3

听起来你想要从你的描述中结合三个列表而不是获得一个列表列表，例如。

var list1 = new List<KeyValuePair<string, string>> { 
        new KeyValuePair<string,string>("key1","2"), 
        new KeyValuePair<string,string>("key2","5"),
        new KeyValuePair<string,string>("key3","20")
    };

var list2 = new List<KeyValuePair<string, string>> { 
        new KeyValuePair<string,string>("key1","2"), 
        new KeyValuePair<string,string>("key2","5"),
        new KeyValuePair<string,string>("key4","10"),
        new KeyValuePair<string,string>("key5","A"),
        new KeyValuePair<string,string>("key6","B"),
        new KeyValuePair<string,string>("key7","C")
    };

var list3 = new List<KeyValuePair<string, string>> { 
        new KeyValuePair<string,string>("key10","2"), 
        new KeyValuePair<string,string>("key20","5"),
        new KeyValuePair<string,string>("key4","10"),
        new KeyValuePair<string,string>("key40","2")
    };

var unionedList = new List<KeyValuePair<string, string>>();

unionedList.AddRange(list1.Union(list2).Union(list3));

foreach (var kvp in unionedList)
{
    Console.WriteLine(string.Format("{0} {1}", kvp.Key, kvp.Value));    
}

unionedList现在将根据您的预期输出包含不同的KeyValue对列表。如果值不同，您将获得重复的密钥。

有效地合并列表列表

3 个答案: