LINQ Grouping help

Question

I have a list like this,

TYPE            FROM            TO  
voice           CALLER_A    CALLER_B    
text            CALLER_A    CALLER_C    
voicemail       CALLER_A    CALLER_B    
voice           CALLER_A    CALLER_B    
text            CALLER_A    CALLER_C    

I want to have a count How many time FROM Called TO By using TYPE

TYPE            FROM            TO  COUNT
voice           CALLER_A    CALLER_B    2
voicemail       CALLER_A    CALLER_B    1
text            CALLER_A    CALLER_C    2

How to I do this. Please Advice

Answer 1

You can group on a annonymous class in C#. I wrote the following example that demonstrates this:

void Main()
{
    // This is the list from your example.
    var contactmoments = new List<ContactMoment> {
        new ContactMoment { From = "CALLER_A", To = "Caller_B", Type = ContactType.Voice },
        new ContactMoment { From = "CALLER_A", To = "Caller_C", Type = ContactType.Text },
        new ContactMoment { From = "CALLER_A", To = "Caller_B", Type = ContactType.VoiceMail },
        new ContactMoment { From = "CALLER_A", To = "Caller_B", Type = ContactType.Voice },
        new ContactMoment { From = "CALLER_A", To = "Caller_C", Type = ContactType.Text }
    };

    // Group by the properties 'From', 'To' and 'Type'
    var groups = contactmoments.GroupBy(c => new { c.From, c.To, c.Type });

    // Write the properties of the key and the size of the group to the console.
    foreach(var group in groups)
    {
        Console.WriteLine("{0,-15} {1,-15} {2,-15} {3}", group.Key.Type, group.Key.From, group.Key.To, group.Count());
    }
}

class ContactMoment
{
    public string From { get; set; }
    public string To { get; set; }
    public ContactType Type { get; set; }
}

enum ContactType
{
    Voice = 1,
    Text = 2,
    VoiceMail = 3
}

This will give the following output:

Voice           CALLER_A        Caller_B        2
Text            CALLER_A        Caller_C        2
VoiceMail       CALLER_A        Caller_B        1

Answer 2

If I understand the question correctly, something like this should work:

void Main()
{
    var list = new List<CallRecord>();
    list.Add(new CallRecord { Type="voice", From="CALLER_A", To="CALLER_B" });
    list.Add(new CallRecord { Type="text", From="CALLER_A", To="CALLER_C" });
    list.Add(new CallRecord { Type="voicemail", From="CALLER_A", To="CALLER_B" });
    list.Add(new CallRecord { Type="voice", From="CALLER_A", To="CALLER_B" });
    list.Add(new CallRecord { Type="text", From="CALLER_A", To="CALLER_C" });

    var groups = (from cr in list 
                  group cr by new {cr.Type, cr.From, cr.To} 
                  into g
                  select g);

    foreach(var group in groups)
        Console.WriteLine("{0} - Count: {1}", group.Key, group.Count());
}

public class CallRecord
{
    public string Type { get; set; }
    public string From { get; set; }
    public string To { get; set; }
}