I need to use Directory.GetFiles but with a few more conditions - vb.net

Question

Here's an example. Lets say I have two files in a directory:
Filename_v1.pdf
Filename_v1_ABC.pdf
Here's some code:
Dim StorageRoot = "SomePath"
Dim RootName = "Filename"
Dim Suffix = "_v"
Dim matchingFiles as string()
matchingFiles = Directory.GetFiles(StorageRoot, Path.GetFileNameWithoutExtension(file.FileName.ToString) + "*.*")
This returns both files mentioned above, but I need to only match files where the first * in *.* if it is numeric. So I need it to ignore a file if it has anything other than a number after the Suffix.
---- Edit ----
It chewed some of my example. Here's some pseudo code:
matchingFiles = Directory.GetFiles(StorageRoot, Path.GetFileNameWithoutExtension(file.FileName.ToString) + "onlyifitisnumeric.*")

Answer 1

One possibility would be to use Regular expressions in order take only those file whose name is matching the pattern you want to have and filter the result from GetDirectory. The pattern in this case could be:
.*_v[0-9]\.pdf
meaning
.*_v <- all symbols followed by "_v"
[0-9] <- followed by a number
\.pdf <- followed by ".pdf"
The pattern can also use the \d character class that means Matches any decimal digit. and makes the pattern shorter:
.*_v\d\.pdf
And the code can look like this:
dim path = "d:\\temp\\xml\\"
dim files = Directory.GetFiles(path, "*.pdf")
Dim rx = new Regex(".*_v\d\.pdf") ' or Dim rx = new Regex(".*_v[0-9]\.pdf")
for each file in files
if rx.IsMatch(file) then
' do something with the file
Console.WriteLine(file)
end if
next file
If you want your code to be succinct then you could use LINQ to Objects:
dim path = "d:\\temp\\xml\\"
dim files = Directory.GetFiles(path, "*.*")
Dim rx = new Regex(".*\d\.pdf") ' or Dim rx = new Regex(".*[0-9]\.pdf")
dim filteredFiles = files.Where(function(file) rx.IsMatch(file))

Answer 2

Here is a sample:
Imports System.Text.RegularExpressions
Imports System.IO
[...]
Dim rx As New Regex("^filename_v\d$")
Dim f = (From fItem As String In IO.Directory.GetFiles("PathToFiles")
Where rx.IsMatch(IO.Path.GetFileNameWithoutExtension(fItem))
Select fItem).ToArray
' Test Output
MessageBox.Show(String.Join(vbCrLf, f))
Use Regex("^filename_v\d+$") to match numbers of any length.

Answer 3

Here what you can do. First Get files with _v*_*, which possible using regular wildcards. Then, apply additional pattern you need to get the subset of files.
Dim files As IEnumerable(Of String) = _
Directory.GetFiles("your path", "your initial optional wildcard").Where(Function(f) Regex.IsMatch(f, "<your pattern>"))