CODEWITHSUNDEEP
c#linq
JJ.
JJ.

Reputation: 9960

get distinct count of substring of file name

I have a directory with a list of file names.

VAH007157100-pic1.jpg
VAH007157100-pic2.jpg
VAH007157100-pic3.jpg

WAZ009999200-pic1.jpg
WAZ009999200-pic2.jpg
WAZ009999200-pic3.jpg

I want to know the distinct count of substringing (0, 12).

This isn't working for some reason:

string[] originalFiles = Directory.GetFiles(SelectedDirectory);

private int GetDistinctPolicyCountInDirectory()
        {
            var prefixes = originalFiles
                .GroupBy(x => x.Substring(0, 12))
                .Select(y => new { Policy = y.Key, Count = y.Count() });

            return prefixes.Count();
        }

I keep getting 0. Am I missing anything here?

Please note that I do not want to do a split to get the numbers separated. I want to do it by substringing.

UPDATE - 

private int GetDistinctPolicyCountInDirectory(string[] originalFiles)
        {
            var count = originalFiles.Distinct(x => Path.GetFileName(x).Substring(0, 12)).Count();

            return Convert.ToInt32(count);
        }

I'm running into an error here where it says: Error 1 Cannot convert lambda expression to type 'System.Collections.Generic.IEqualityComparer' because it is not a delegate type

Upvotes: 1

Views: 1121

Answers (2)

Jon Egerton
Jon Egerton

Reputation: 41569

I'd just consider using .Distinct().

Also you need to strip it down to just the filename instead of the full file path.

originalFiles.Select(x => Path.GetFileName(x).Substring(0, 12))
             .Distinct().Count();

Upvotes: 6

Julien Lebosquain
Julien Lebosquain

Reputation: 41243

GetFiles returns an array of file names with full paths, including the directory. You want to compare only the file name, so you should consider using Path.GetFileName.

GroupBy(x => Path.GetFileName(x).Substring(0, 12));

Upvotes: 2

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