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c#linqforeachinteger
Wilson
Wilson

Reputation: 8768

Writing a LINQ statement that will add values for each list element

Firstly, I have a helper method that will return the number of files in a list that have a given extension. I want to get the number of audio files overall in a given list, and I have a list of the audio extensions used.

public List<string> accepted_extensions = {"mp3", "wav", "m4a", "wma", "flac"};

Helper method:

private int getFileTypeCount(string[] files, string ext)
    {
        int count = 0;
        foreach (string file in files) if (Path.GetExtension(file).Contains(ext))
            {
                count++;
            }
        return count;
    }

So, I wanted to see if it was possible to write a ForEach with LINQ that would add teh result of each method with a list and the given extension to an integer. I'm not very good with LINQ, so I started with:

int audio_file_count = accepted_extensions.ForEach(i => getFileTypeCount(new_file_list.ToArray(),i));

but I'm not sure how to go about adding the number returned by the helper method to a total. I know this could easily be done with a regular foreach loop, I was just interested o see if it was possible with LINQ.

Upvotes: 1

Views: 916

Answers (5)

I4V
I4V

Reputation: 35353

var count = files
         .Count(f => accepted_extensions.Any(x => Path.GetExtension(f).EndsWith(x)));

Upvotes: 0

Parimal Raj
Parimal Raj

Reputation: 20575

    static void Main(string[] args)
    {
        List<string> accepted_extensions = new List<string> {".mp3", ".wav", ".m4a", ".wma", ".flac"};

        string[] files = new string[] {};

        int count = files.Count(file => accepted_extensions.Contains(Path.GetExtension(file)));
    }

Upvotes: 0

Tommaso Belluzzo
Tommaso Belluzzo

Reputation: 23675

You could try this:

Int32 count = files.Count(file => Path.GetExtension(file).Contains(ext));

Upvotes: 0

e_ne
e_ne

Reputation: 8459

You can use the Sum method. Modify your query in this way:

int audio_file_count = accepted_extensions.
    Sum(extension => getFileTypeCount(new_file_list.ToArray(), extension));

Upvotes: 2

Darin Dimitrov
Darin Dimitrov

Reputation: 1038730

You could use the .Count() extension method to perform an aggregation over the resultset:

private int GetFileTypeCount(string[] files, string ext)
{
    return files.Count(file => Path.GetExtension(file).Contains(ext));
}

Upvotes: 3

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