CODEWITHSUNDEEP
c#linq
Icemanind
Icemanind

Reputation: 48686

Need a LINQ query to find string items

I have a List<NameClass> that stores a collection of NameClass items with a property called Name in the class. What I'm trying to do is write a Linq query that will pull all the names that start with Jones, but only if there are 3 or more occurrences. For example, if my list had the following items:

Name
-----------
Jones
Jonestown
Smith
Hector
Jones
Smith
Smith

I am looking for a C# function that I can call like this:

GetNames("Jones");

And it should return:

Jones
Jonestown
Jones

And if I run this:

GetNames("Smith");

It should return:

Smith
Smith
Smith

And if I run this:

GetNames("Hector");

It should return nothing since Hector isn't in the list 3 or more times.

Any help writing this LINQ query would be appreciated!

Upvotes: 1

Views: 9555

Answers (6)

Omar
Omar

Reputation: 16623

IEnumerable<NameClass> GetNames(string s, List<NameClass> list)
{
    var filtered = list.Where(l => l.Name.StartsWith(s));
    return filtered.Count() >= 3 ? filtered : null;
}

Upvotes: 2

nemesv
nemesv

Reputation: 139758

A "one liner":

public string[] GetNames(MyClass[] list, string prefix)
{
    return list
        .Where(item => 
            item.Name.StartsWith(prefix) && 
            list.Count(temp => temp.Name.StartsWith(prefix)) > 2)
        .Select(l => l.Name)
        .ToArray();
}

Upvotes: 1

Tim Schmelter
Tim Schmelter

Reputation: 460108

I think you're looking for something like this, aren't you?

public static IEnumerable<NameClass> GetNames(IEnumerable<NameClass> names, String name, int minCount)
{
    var matchingNames = names.Where(n => n.Name.StartsWith(name));
    if (matchingNames.Count() >= minCount)
    {
        return matchingNames.ToList();
    }
    else
    {
        return null;
    }
}

var jones = GetNames(names, "Jones", 3);

Upvotes: 2

code4life
code4life

Reputation: 15794

Have you tried this?

public void GetNames(string pattern)
{
    var q = from n in names
        where n.Name.StartsWith(pattern)
        select n;

    if (q.Count() >= 3)
        return q.ToList();
    else
        return new List<NameClass>();
}

Upvotes: 2

ChrisWue
ChrisWue

Reputation: 19020

If you don't need it all in one query this extension method should do it:

public static IEnumerable<string> GetNames(this IEnumerable<string> list, string prefix, int minOccurences)
{
    var res = list.Where(x => x.StartsWith(prefix));
    return res.Count() >= minOccurences ? res : new string[0];
}

Upvotes: 1

Doguhan Uluca
Doguhan Uluca

Reputation: 7323

string searchString = "Jones";
string lowerSS = searchString.ToLower();

List<NameClass> nameClasses; 

var results = nameClasses.Where(nc => nc.Name.ToLower().StartsWith(lowerSS));

if(results != null && results.Count() >= 3)
{
    return results;
}
else
{
    return null;
}

Upvotes: 7

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