Using Directory.GetFiles with a Regular Expression Filter

Question

I have a folder with two files:

• Awesome.File.20091031_123002.txt
• Awesome.File.Summary.20091031_123152.txt

In addition, a third-party application processes files as follows:

• Reads folderPath and searchPattern from the database
• Performs Directory.GetFiles(folderPath, searchPattern) , processes all files matching the filter, and then moves the files to the archive folder.

It turns out that I need to move two files to different archive folders, so I need to process them separately, providing different search parameters to select them separately. Please note that I cannot change the third-party application, but I can change the addresses of searchPattern and files in my database.

What does searchPattern allow me to select Awesome.File.20091031_123002.txt without including Awesome.File.Summary.20091031_123152.txt ?

Answer 1

Awesome.File. ???????? _ ??????. Txt

The question mark (?) Acts as a single character holder.

Answer 2

If you are going to use LINQ, then ...

  var regexTest = new Func<string, bool>(i => Regex.IsMatch(i, @"Awesome.File.(Summary)?.[\d]+_[\d]+.txt", RegexOptions.Compiled | RegexOptions.IgnoreCase)); var files = Directory.GetFiles(@"c:\path\to\folder").Where(regexTest); 

Answer 3

I wanted to try my meager linq skills here ... I'm sure there is a more elegant solution, but here's mine:

 string pattern = ".SUMMARY."; string[] awesomeFiles = System.IO.Directory.GetFiles("path\\to\\awesomefiles"); IEnumerable<string> sum_files = from file in awesomeFiles where file.ToUpper().Contains(pattern) select file; IEnumerable<string> other_files = from file in awesomeFiles where !file.ToUpper().Contains(pattern) select file; 

This assumes that there are no files other than two in another directory, but you can customize the template here to suit your needs (ie add “Awesome.File” to the top of the template.)

When you repeat the assembly of each of them, you should get what you need.

Answer 4

According to the documentation , searchPattern only supports ***** and ? Wildcards . You will need to write your own regular expression filter that will take the results of Directory.GetFiles and apply further filtering logic.

Answer 5

If you do not want to use Linq, here is one way.

Public Sub FileChecker (ByVal filePath As String)

  Dim di As New DirectoryInfo(filePath) Dim _MatchCounter As Integer Dim RegexPattern As String = "^[a-zA-Z_a-zA-Z_a-zA-Z_0-9_0-9_0-9.csv]*$" Dim RegexPatternMatch As New Regex(RegexPattern, RegexOptions.IgnoreCase) For Each matchingFile As FileInfo In di.GetFiles() Dim m As Match = RegexPatternMatch.Match(matchingFile.Name) If (m.Success) Then MessageBox.Show(matchingFile.Name) _MatchCounter += 1 End If Next End Sub