检查文件名在FileInfo数组中是否存在多次

Question

FileInfo[] folderFiles = folder.GetFiles();

foreach (FileInfo file in folderFiles)
{

    int fileCount = 0;

    StreamWriter sw = null;

    string fileName = Path.GetFileNameWithoutExtension(file.Name);

    string[] brkedfilename = fileName.Split('_');

    string stringToCheck = brkedfilename[3];

    for (int i = 0; i <= folderFiles.Count() - 1; i++)
    {
        string fileName2 = folderFiles[i].Name;

        string[] brkedfilename2 = fileName2.Split('_');

        if (brkedfilename2[3] == stringToCheck)
        {
            fileCount = ++fileCount;

            if (fileCount == 2)
           {
                sw = new StreamWriter(folderPath + "/" + newFileName, true);
                sw.WriteLine(stringToCheck + "  " + "--" + "  " + "Repeated in folder " + " " + folder.Name);
                sw.Close();
            }
        }
    }
}

By doing this way, if a file name is existing 2 times , it is writing that file name 2 times. But I want it to write only once.

Any help would be appreciated. Thanks in advance. :)

Answer 1

You can use LINQ to find files with same brkedNames:

var repeatedFiles = from f in folderFiles
                    let brkedName = Path.GetFileNameWithoutExtension(f.Name).Split('_')[3]
                    group f by brkedName into g
                    where g.Count() > 1
                    select new
                    {
                        BrkedName = g.Key,
                        Count = g.Count(),
                        Files = g
                    };

This query groups all files by 4th part of splitted names (note: as in your original code I don't check if there is at least 4 parts) and then select groups with more than one file. It also provides some stats - brked name, count of files with same name and files collection.

foreach(var group in repeatedFiles)
   sw.WriteLine($"{group.BrkedName} -- repeated {group.Count} times in {folder.Name}");

Answer 2

I propose use a hashset. Hashset cannot contain duplicate elements. When You add duplicate element do hashset method Add return false and program go on witout error but hashset will not take duplicate element

var duplicate = new HashSet<string>();

    foreach (FileInfo file in folderFiles)
    {
        int fileCount = 0;

        StreamWriter sw = null;

        string fileName = Path.GetFileNameWithoutExtension(file.Name);

        string[] brkedfilename = fileName.Split('_');

        string stringToCheck = brkedfilename[3];

         if (!duplicate.Add(stringToCheck))
            {
                sw = new StreamWriter(folderPath + "/" + newFileName, true);
                sw.WriteLine(stringToCheck + "  " + "--" + "  " + "Repeated in folder " + " " + folder.Name);
                sw.Close();
            }
    }

Program adds each element do Hashset duplicate when element is in Hashset already Add metod return false when I know the element is in the Hashset and I save in the file as You want

Answer 3

You can use Dictionary ( filename, repeat time) to list all filename exist. And after that you can loop the dictionary to write to console.