Search exception filter

Hello people,

I have made following code that gather each path for all folders and subfolders in a certain path.
my result generates approx 6000 different items.

Now I need to exclude some folders.

My first question:
is the fastest way to make a list of items that is exceptions in my searchfunction of what I am not intrested in?

because I have got several folders I don't want to find and its always the same pattern.
if how?

this is my code

Code:

---

    Private Sub Button2_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

        For Each d In Directory.EnumerateDirectories("C:\", "*.*", SearchOption.AllDirectories)
            Dim myPath = ((d.ToString()))

            Console.WriteLine(myPath)
        Next
    End Sub

---

or will I add all items as they are to a new list (this take ages years!) then clean unwanted items from the list.

Here is an example of my result from the code:


C:\Archive\custommers\original-files\32001-33000\32100\32099\
C:\Archive\custommers\original-files\32001-33000\32100\32099\hello\
C:\Archive\custommers\original-files\32001-33000\32100\32099\dontuseme\
............. and so on........

C:\Archive\custommers\original-files\33001-34000\33100\33099\
C:\Archive\custommers\original-files\33001-34000\32100\33099\hello\
C:\Archive\custommers\original-files\33001-34000\32100\33099\dontuseme\

.............and so on......


and so on.....

Could someone help me?

Thank you in advance !

Intuitively, it's probably faster to write a loop that looks like:

Code:

---

For Each directoryPath In Directory.EnumerateDirectories(...)
    If IsGood(directoryPath)
        Console.WriteLine(myPath)
    End If
Next

---

This only has to go over the list once. If you do it the other way, you have to iterate at least twice: once to build the list, then a second time to remove items you don't want. But it's also trickier, because iterating over a list while you are changing it takes a little more care.

I think your second question is "How do I find folders that match a certain pattern?" That'll depend on the pattern, but a Regex is probably a workable choice here. For example, this function would enumerate and reject the paths that end with "dontuseme":

Code:

---

Sub PerformEnumeration()
    For Each directoryPath In Directory.EnumerateDirectories(...)
        If IsGood(directoryPath)
            Console.WriteLine(myPath)
        End If
    Next
End Sub

Function IsGood(ByVal directoryPath as String) As Boolean
    Dim badPattern = "\\\d+\\dontuseme\\$"
    Return Not System.Text.RegularExpressions.IsMatch(directoryPath, badPattern)
End Function

---

That regular expression says "Match strings that end with a \ followed by any number of digits, another \, the string "dontuseme", and one more backslash". They are convenient for matching certain strings, but there might be better ways if your pattern is more complex.