CODEWITHSUNDEEP
c#linqc#-4.0
Nilesh Barai
Nilesh Barai

Reputation: 1322

Linq query to obtain count from a List

I am trying to construct a LINQ query in c# for the following scenario.

"Given a particular token "to identify the count of documents in which it exists"

private List<Document> documents = new List<Document>();

class Document
{
    string filename;
    public string FileName { get { return filename; } }
    Dictionary<string, int> tokens;
    public Dictionary<string, int> Tokens { get { return tokens; } }

    public Document(string filename, Dictionary<string, int> tokens)
    {
        this.filename = filename;
        this.tokens = tokens;
    }
}

With my knowledge I came up with this expression:

documents.Where(d => d.Tokens.Keys.Any(k => k == word)).Count();

But I am not sure whether it is 100% correct. In need of some expert advice on this.

Upvotes: 1

Views: 72

Answers (2)

Magnus
Magnus

Reputation: 46909

To make use of the O(1) lookup time of the dictionary you should use ContainsKey instead.

documents.Count(d => d.Tokens.ContainsKey(word));

Upvotes: 3

jnovo
jnovo

Reputation: 5769

You can actually perform the filtering in the Count method:

documents.Count(d => d.Tokens.Keys.Any(k => k == word));

Beyond that, I think your query is correct.

Upvotes: 1

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