LINQ Select Range Of Orders By Surname

Question

I guess this is probably going to be obvious in retrospect but I am finding it very hard to get my head round this.

Basically I just want to use LINQ to Objects to select from a range of objects with a surname property the surnames alphabetically between two surnames e.g. in the list:

Adams
Bentham
Bickford
Gillies
Kelly
Moore
Peters
Rutherford
Smith
Taylor
Williams

If you selected from "Kelly" to "Smith" it would return:

Kelly
Moore
Peters
Rutherford
Smith

inclusive.

It has to be specific enough that in the case where one were to select Kelly to Smith and there was a Kellerman before and a Smythe after the query would leave those out so LIKE 'K%' and LIKE 'S%' are no good. Besides you'd have to go through all the letters inbetween k and s to get there.

I am likely just being foolish in the way I'm putting the question to Google but no one else seems to have this alphabetic concern. Hope someone can help.

EDIT: So far so good folks. But here's a brainrtwister. We want to set a Maximum number of records returned.

e.g If we ask for Bickford to Rutheerford with a max of 3 we should get back:

Bickford
Gillies
Kelly

At present we just get three of the names between the goalposts at random.

Any ideas?

Answer 1

I think you're looking for something like this

static IEnumerable<string> GetNames(IEnumerable<string> originalList, string fromName, string toName)
{
    foreach (string name in originalList)
    {
        if (name.CompareTo(fromName) >= 0 && name.CompareTo(toName) <= 0)
            yield return name;
    }
}

Or the LINQ version

static IEnumerable<string> GetNames(IEnumerable<string> originalList, string fromName, string toName)
{
    var query = from name in originalList
                where name.CompareTo(fromName) >= 0 && name.CompareTo(toName) <= 0
                select name;

    return query;
}

Example usage to product your Kelly to Smith inclusive list

string[] surnames = { "Adams", "Bentham", "Bickford", "Gillies", "Kelly", "Moore", "Peters", "Rutherford", "Smith", "Taylor", "Williams" };

foreach (string name in GetNames(surnames, "Kelly", "Smith"))
    Console.WriteLine(name);

Answer 2

I think this should do it:

var Names = SourceList.OrderBy(x => x.SurName).Select(x => x.SurName >= "Kelly")
            .Select(x => x.SurName <= "Smith").ToList();

I may be very wrong. Still new with all this.

Answer 3

what about something like

names
    .Where(n => n.surname.CompareTo(fromName) >= 0)
    .Where(n => n.surname.CompateTo(toName) <= 0)

Answer 4

    public IEnumerable<UserListItem> GetFilteredUsers(String start, String end)
    {
        var Users = from u in User.GetUsers()
                    let firstLetter = Char.ToUpper(u.FirstName[0])
                    let startLetter = Char.ToUpper(start[0])
                    let endLetter = Char.ToUpper(end[0])
                    where firstLetter >= startLetter && firstLetter <= endLetter
                    orderby u.FirstName
                    select u;
    }

Answer 5

How about:

var results = Users
    .OrderBy(x => x.Surname)
    .SkipWhile(x => x.Surname.CompareTo("Kelly") < 0)
    .TakeWhile(x => x.Surname.CompareTo("Smith") <= 0);