按列表行linq中单词出现次数计数排序

Question

如何根据linq数据的每一行中单词的出现情况对列表进行排序？我从这里得到了一个给出正确输出的人的答案。代码如下：

void Main()
{
    List<SearchResult> list = new List<SearchResult>() { 
        new SearchResult(){ID=1,Title="Geo Prism GEO 1995 GEO* - ABS #16213899"},
        new SearchResult(){ID=2,Title="Excavator JCB - ECU P/N: 728/35700"},
        new SearchResult(){ID=3,Title="Geo Prism GEO 1995 - ABS #16213899"},
        new SearchResult(){ID=4,Title="JCB Excavator JCB- ECU P/N: 728/35700"},
        new SearchResult(){ID=5,Title="Geo Prism GEO,GEO 1995 - ABS #16213899 GEO"},
        new SearchResult(){ID=6,Title="dog"},
    };

    var to_search = new[] { "Geo", "JCB" };

    var result = from searchResult in list
         let key_string = to_search.FirstOrDefault(ts =>  searchResult.Title.ToLower().Contains(ts.ToLower()))
         group searchResult by key_string into Group
         orderby Group.Count() descending
         select Group;
         result.ToList().Dump();



 }
// Define other methods and classes here
public class SearchResult
{
    public int ID { get; set; }
    public string Title { get; set; }
}

我得到的输出如下

ID Title 
-- ------
1  Geo Prism GEO 1995 GEO* - ABS #16213899 
3  Geo Prism GEO 1995 - ABS #16213899 
5  Geo Prism GEO,GEO 1995 - ABS #16213899 GEO 
2  Excavator JCB - ECU P/N: 728/35700 
4  JCB Excavator JCB- ECU P/N: 728/35700 
6  dog 

上面的输出是ok的。具有顺序GEO的所有行都排在第一位，因为它在大多数行中发现了最大时间，这意味着GEO是在3行中找到的单词，而JCB是在两行中找到的，因此与JCB相关的行紧随其后。

我需要另一个排序后，得到上述输出的整个数据。也就是说，GEO行首先出现在具有GEO字最大时间的行中。因此，我的输出将如下所示：

ID Title 
-- ------
5  Geo Prism GEO,GEO 1995 - ABS #16213899 GEO 
1  Geo Prism GEO 1995 GEO* - ABS #16213899 
3  Geo Prism GEO 1995 - ABS #16213899 
4  JCB Excavator JCB- ECU P/N: 728/35700 
2  Excavator JCB - ECU P/N: 728/35700 
6  dog 

我发现了一个linq查询，它统计字符串中某个单词的出现次数：

string text = @"Historically, the world of data and data the world of objects data" ;
string searchTerm = "data";
//Convert the string into an array of words
string[] source = text.Split(new char[] { '.', '?', '!', ' ', ';', ':', ',' },   StringSplitOptions.RemoveEmptyEntries);
var matchQuery = from word in source
             where word.ToLowerInvariant() == searchTerm.ToLowerInvariant()
             select word;
int wordCount = matchQuery.Count();

我是从this url买的

如何使用上面的代码对标题进行排序？如何使用第二个排序来计算一个单词在标题字段中的出现次数，结果我的输出将如下所示：

ID Title 
-- ------
5  Geo Prism GEO,GEO 1995 - ABS #16213899 GEO 
1  Geo Prism GEO 1995 GEO* - ABS #16213899 
3  Geo Prism GEO 1995 - ABS #16213899 
4  JCB Excavator JCB- ECU P/N: 728/35700 
2  Excavator JCB - ECU P/N: 728/35700 
6  dog 

Answer 1

在此行之后：

var result = from searchResult in list
         let key_string = to_search.FirstOrDefault(ts =>  searchResult.Title.ToLower().Contains(ts.ToLower()))
         group searchResult by key_string into Group
         orderby Group.Count() descending
         select Group;

你想要这样的东西：

foreach (var group in result) {
      foreach (var item in group.OrderByDescending(theItem => WordCount(theItem.Title, group.Key))) {
          Console.WriteLine(item.Title);
      }
}

添加了一个方法，如下所示：

public static int WordCount(string haystack, string needle) {
    if (needle == null) {
        return 0;
    }
    string[] source = haystack.Split(new char[] { '.', '?', '!', ' ', ';', ':', ',' }, StringSplitOptions.RemoveEmptyEntries);
    var matchQuery = from word in source
                        where word.ToLowerInvariant() == needle.ToLowerInvariant()
                        select word;
    return matchQuery.Count();
}

Answer 2

使用WordCount作为字符串的扩展方法，然后可以使用简单的Lambda表达式：

list.OrderByDescending(sR => sR.Title.WordCount( to_search ))

如果您想省略所有没有任何搜索词的结果，可以使用Where子句。也就是说。

IEnumerable<SearchResult> results = list
                .Where( sR => sR.Title.WordCount( searchTerms ) > 0 )
                .OrderByDescending( sR => sR.Title.WordCount( searchTerms ) );

编辑如果搜索词具有优先级，则可以对每个项目执行多个排序，如下所示(首先按优先级最低的元素排序，然后按下一个排序，直到最后排序在优先级最高的项目上)：

string[] searchTerms = new string[]{ "GEO","JCB" };
IEnumerable<SearchResult> results = list;
foreach( string s in searchTerms.Reverse() ) {
    results = results
        .OrderByDescending( sR => sR.Title.WordCount( s ) );
}

扩展方法：

static class StringExtension{
        public static int WordCount( this String text, string searchTerm )
        {
            string[] source = text.Split( new char[] { '.', '?', '!', ' ', ';', ':', ',' }, StringSplitOptions.RemoveEmptyEntries );
            var matchQuery = from word in source
                             where word.ToLowerInvariant() == searchTerm.ToLowerInvariant()
                             select word;
            int wordCount = matchQuery.Count();
            return wordCount;
        }
        public static int WordCount( this String text, IEnumerable<string> searchTerms ) {
            int wordCount = 0;
            foreach( string searchTerm in searchTerms ) {
                wordCount += text.WordCount( searchTerm );
            }
            return wordCount;
        }
    }

Answer 3

这样如何：

IEnumerable<SearchResult> result =
    from searchResult in list
    let key_string = to_search.FirstOrDefault(ts => searchResult.Title.ToLower().Contains(ts.ToLower()))
    group searchResult by key_string into Group
    orderby Group.Count() descending
    from item in Group.OrderByDescending(theItem => WordCount(theItem.Title, Group.Key))
    select item;

使用以下WordCount方法：

public static int WordCount( String text, string searchTerm )
{
    string[] source = text.Split( new char[] { '.', '?', '!', ' ', ';', ':', ',' }, StringSplitOptions.RemoveEmptyEntries );
    var matchQuery = from word in source
                     where word.ToLowerInvariant() == searchTerm.ToLowerInvariant()
                     select word;
    int wordCount = matchQuery.Count();
    return wordCount;
}

我注意到的一个小问题是，不包含匹配词的标题将被组合在一起，因此可以将它们放在具有匹配词的标题之前。