MMDDYYYY filenames sorting using C#.net

Question

Hi All,

I have 5 files like the following abc_12292020.txt, abc_12302020.txt, abc_12312020.txt, abc_01012021.txt, abc_01022021.txt

Now when I am trying to load these files in ascending order its loading in abc_01012021.txt, abc_01022021.txt, abc_12292020.txt, abc_12302020.txt, abc_12312020.txt order.

Here is the C# code I am using

rows.Sort((a, b) => string.Compare(a["Name"].ToString(), b["Name"].ToString()));

Please suggest.

Regards

Raj

Answer 1

What about

rows.Sort((a, b) => string.Compare(
                 a.["Name"].substring(a.["Name"].Length-4) + a["Name"].ToString(), 
                 b.["Name"].substring(b.["Name"].Length-4) + b["Name"].ToString());

I don't know why you were using ToString. I left it out since I assume that you already has an array of strings, but if not you will have to add ToString to what I added.

Warning: I'm a T-SQL guy who only do C# left-handedly.

Answer 2

I manage this type of process in SSIS using a script task - that loads an object variable (recordset). I then use a foreach container and loop over the recordset to process the files in order by the date stamp. The object is defined as a dataset (unsorted) - then we use a data view to sort the rows, convert the data view back to a dataset (sorted) and return the sorted dataset in the object.

In that code - we do the following:

            foreach (FileInfo file in files)
            {
                // Get File Date from file name
                string fileName = Path.GetFileNameWithoutExtension(file.Name);
                DateTime fileDate = DateTime.ParseExact(fileName.Substring(fileName.Length - 8), "yyyyMMdd", provider);

                < other code here >
            }

Our files have a date stamp in the format YYYYMMDD - so when we parse the date that is the format we use. You can change the format to "MMddyyyy" - which will then set an actual date that can be sorted by the date value and not a string. Note: provider is defined as:

            IFormatProvider provider = null;

Answer 3

I highly suggest you change your file naming convention to "YYYYMMDD_abc.txt" instead. Then your files will naturally sort without issue.