How to get files from 1 to n in a particular pattern?

Question

Suppose you have files like:

NewFile.part01.zip
NewFile.part02.zip
NewFile.part04.zip
NewFile.part06.zip
NewFile.part07.zip

How do you get the files in this patter so you only get a SINGLE file called "NewFile" and also get the missing ones as integers, in this case (3, 5)

Right now I am checking files one by one and if the name only differs in the suffix then skipping, also checking the number is +1 than the previous, etc.

But I thought someone might have a better, more elegant way of doing this. Linq, regex, etc?

EDIT:

So the way to know when the continuous files end is when the last file size has a difference than others. So it's like 200mb, 200mb, 200mb, ..., then the last one is 196mb.

My input is the full file list with the path like:

"C:\NewFile.part01.zip"
"C:\NewFile.part02.zip"
...

Answer 1

If you know the file names try something like this (LINQ's "Except"):

string[] seq1 = { "NewFile.part01.zip", "NewFile.part03.zip"};
string[] seq2 = { "NewFile.part01.zip", "NewFile.part02.zip", "NewFile.part03.zip" };
var diffs = seq2.Except(seq1);

PK :-)

(I just saw your edit but now not so clear on the question)

Answer 2

Okay, first of all, you can extract a number from filename:

int ExtractNumber(string filename)
{
    filename = filename.Remove(filename.LastIndexOf('.'));
    filename = filename.Remove(0, filename.LastIndexOf('.') + 1);
    filename = filename.Remove(0, 4); // "part"
    return int.Parse(filename);
}

Now, you can check the missing numbers.

HashSet<int> existingNumbers = new HashSet<int>();
int max = -1;
foreach (string fn in filenameList)
{
    int n = ExtractNumber(fn);
    existingNumbers.Add(n);
    max = Math.Max(max, n);
}
HashSet<int> nonExistingNumbers = new HashSet<int>();
for (int i = 0; i <= n; i++)
    if (!existingNumbers.Contains(i))
        nonExistingNumbers.Add(i);

Answer 3

In dos, simply type:

copy "c:\NewFile.Part??.zip" "c:\NewFile.zip" /b

Don't forget the /b or it will process command codes differently and turn any '0x0d' or '0x0a' characters into the char pair '0x0d0a'

Answer 4

You can use regex that looks like this

^(?<name>.*)\.part(?<num>\d{0,})\.zip$

which should give you two group matches, one for the filename and one for the num

Do a loop, collect the info and then you can identify the name and numbers (store in a list). If you like you can use linq in loop like this to identify the missing number set

foreach(int i = list.Min(); i <= list.Max(); i++)
{
  if (!list.Contains(i))
    missingNums.Add(i);
}

--- Edited to give example as requested

This is the example how you will use the regex to iterate through your file list

   string pattern = @"^(?<name>.*)\.part(?<num>\d{0,})\.zip$";
    foreach(string file in files)
    {
        Match match = Regex.Match(file, pattern);
        if (match.Success && match.Groups.Count >= 2)
        {
            string filename = match.Groups["name"].Value;
            int num = Convert.ToInt32(match.Groups["num"].Value);
        }
    }