如何使用LINQ检索列表中包含一个列表的多个属性的条目？

Question

I have a List of IJapaneseDictionaryEntry objects which are described below. Inside this are IKanji objects that contain Priorites objects.

I have a rather difficult thing I would like to do and would appreciate any advice / suggestions. What I would like to do is to retrieve entries that have an entry that have Priority of "Frequency1" have Priority of "Frequency2" or Priority of "Frequency3" from the list entries that I created.

public interface IJapaneseDictionaryEntry
{
    int Sequence { get; }
    IEnumerable<IKanji> Kanjis { get; }
    IEnumerable<IReading> Readings { get; }
    IEnumerable<ISense> Senses { get; }
}

Where each object contains a list of IKanji objects

public interface IKanji
{
    string Text { get; }
    IEnumerable<KanjiInformation> Informations { get; }
    IEnumerable<Priority> Priorities { get; }
}

Here's the list:

List<IJapaneseDictionaryEntry> entries = dictionary.GetEntries().ToList();

Here's a view that I think might help explain the contents:

I hope the information here is enough as it seems difficult to explain what I need to retrieve.

Answer 1

var result = entries.Where(e => e.Kanjis.Any(k => k.Priorities.Contains(Priority.Frequency1) ||
k.Priorities.Contains(Priority.Frequency2) ||
k.Priorities.Contains(Priority.Frequency3)
)).ToList();

Considering your 2 questions, I would have made something like this:

[Flags]
public enum Priority
{
     Frequency1 = 1,
     Frequency2 = 2,
     Frequency3 = 4,
     Frequency4 = 8
}

public interface IKanji
{
    string Text { get; }
    IEnumerable<KanjiInformation> Informations { get; }
    Priority Priorities { get; }
}

In above consider each Priority as a bit in an int, you can add priority by using bitwise or ( | ) :

Priorities = Priority.Frequency1 | Priority.Frequency2 // means have both priorities

To check if it has specific priority use bitwise and ( & ):

if((Priorities & Priority.Frequency1) == Priority.Frequency1
{
     // it contains Priority.Frequency1
}

Then the answer you were looking for will be like:

Priority p = Priority.Frequency1 | Priority.Frequency2 | Priority.Frequency3

var result = entries.Where(e => e.Kanjis.Any(k => k.Priorities & p == p)))
.ToList();

Answer 2

This could be one solution:

var filteredEntries = entries.Where( // Only entries
    e => e.Kanjis.Any( // which have one or more kanjis with..
        a => a.Priorities.Any( // which have one or more priorities                    
            p => p.Value == "Frequency1" // which have a value of "Frequency1"
            )));

I changed your interfaces to classes to make it run with some example-data:

public class IJapaneseDictionaryEntry
{
    public int Sequence { get; set; }
    public IEnumerable<IKanji> Kanjis { get; set; }
}
public class IKanji
{
    public string Text { get; set; }
    public IEnumerable<Priority> Priorities { get; set; }
}

public class Priority
{
    public string Value { get; set; }
}

public static void Main(string[] args)
{
    // Initialize 3 objects. One has Priority we're searching
    List<IJapaneseDictionaryEntry> entries = new List<IJapaneseDictionaryEntry>()
    {
        new IJapaneseDictionaryEntry(){ Sequence = 1, Kanjis = new List<IKanji>() { new IKanji() { Priorities = new List<Priority>() { new Priority() { Value = "Frequency1" } } } } },
        new IJapaneseDictionaryEntry(){ Sequence = 2, Kanjis = new List<IKanji>() { new IKanji() { Priorities = new List<Priority>() { new Priority() { Value = "Frequency2" } } } } },
        new IJapaneseDictionaryEntry(){ Sequence = 3, Kanjis = new List<IKanji>() { new IKanji() { Priorities = new List<Priority>() { new Priority() { } } } } },
    };

    // Here's the magic:
    var filteredEntries = entries.Where( // Only entries
        e => e.Kanjis.Any( // which have one or more kanjis with..
            a => a.Priorities.Any( // which have one or more priorities                    
                p => p.Value == "Frequency1" // which have a value of "Frequency1"
                )));

    // Let's check the output
    foreach (var e in filteredEntries)
    {
        Console.WriteLine(e.Sequence);
    }
}