Count File Extensions and Group it using LINQ

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We have this application where a service reads files generated in a folder every hour and returns a string array containing the file names. A simple report needed to be generated which showed the count of files grouped by the file extension.

Here’s how it can be done using LINQ

public static void Main()
{
    // Assuming the array with file names is returned via a service
    string[] arr = {"abc1.txt", "abc2.TXT",
    "xyz.abc.pdf", "abc.PDF", "abc.xml", "zy.txt" };

    var extGrp = arr.Select(file => Path.GetExtension(file)
                                        .TrimStart('.').ToLower())
             .GroupBy(x => x,
                      (ext, extCnt) =>
                          new
                          {
                              Extension = ext,
                              Count = extCnt.Count()
                          });
    // Print values
    foreach (var a in extGrp)
        Console.WriteLine("{0} file(s) with {1} extension ",
            a.Count, a.Extension);
    Console.ReadLine();
}

In the code above, we first use the Path.GetExtension to get the extension of the specified file and then use GroupBy to count the number of files for each extension.

OUTPUT

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About The Author

Suprotim Agarwal, Developer Technologies MVP (Microsoft Most Valuable Professional) is the founder and contributor for DevCurry, DotNetCurry and SQLServerCurry. He is the Chief Editor of a Developer Magazine called DNC Magazine. He has also authored two Books - 51 Recipes using jQuery with ASP.NET Controls. and The Absolutely Awesome jQuery CookBook.

Follow him on twitter @suprotimagarwal.