CODEWITHSUNDEEP
c#linq
Arun Babu A
Arun Babu A

Reputation: 72

Linq to Objects - converting query form to dot notation when let clause is involved

While reading Linq to Objects from msdn I got a sample query https://msdn.microsoft.com/en-us/library/bb546163.aspx The example was in linq query form which I tried to convert to method form. The query includes a let keyword. I need suggestion on how the method form I written can be optimized, more specifically how to handle let when converting to method form. So far I tried this much

internal static string[] GetSpecificSentenceContainingParticularWords(
    string sentenceToSearch, 
    string[] WordsToMatch)
{
    if (string.IsNullOrEmpty(sentenceToSearch) 
        || WordsToMatch == null 
        || WordsToMatch.Count() == 0)
        return null;

    string[] sentences = sentenceToSearch.Split(new char[] { '.' });

    var returnSentences = from s in sentences
                          let w = s.Split(new char[] { ' ' })
                          where w.Distinct().Intersect(WordsToMatch).Count() 
                                == WordsToMatch.Count()
                          select s;     

    returnSentences = sentences.Where((s) =>
    {
        var a = s.Split(new char[] { ' ' }); //splitting a sentence to words
        return (a.Distinct().Intersect(WordsToMatch).Count() == WordsToMatch.Count());
    });

    return returnSentences.ToArray<string>();
}

Upvotes: 0

Views: 639

Answers (3)

moarboilerplate
moarboilerplate

Reputation: 1643

I personally prefer method syntax for every scenario with the exception of this one. With method syntax you have to store your calculated value as a property on an anonymous object. With query syntax and let you don't have to jump through any hoops.

I would not attempt an "optimization" by converting it to method syntax.

If however you want to optimize the code beyond just converting it to method syntax, you can cut it down to one call to Except and one check that the result is empty.

Upvotes: 0

juharr
juharr

Reputation: 32296

Technically you don't even need the let in the first place

var returnSentences = from s in sentences
                      where s.Split(new char[] { ' ' })
                             .Distinct()
                             .Intersect(WordsToMatch)
                             .Count() == WordsToMatch.Count()
                      select s;

So you could just do

var returnSentences = sentences.Where(s => s.Split(new char[] { ' ' })
                                            .Distinct()
                                            .Intersect(WordsToMatch)
                                            .Count() == WordsToMatch.Count());

Upvotes: 0

Backs
Backs

Reputation: 24913

With help of Resharper:

var returnSentences = sentences.Select(s => new {s, w = s.Split(' ')})
                .Where(@t => @t.w.Distinct().Intersect(WordsToMatch).Count() == WordsToMatch.Count())
                .Select(@t => @t.s);

Upvotes: 1

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