如何篩選具有多個條件的Directory.EnumerateFiles？

Question

我有以下代碼：

List<string> result = new List<string>(); 

foreach (string file in Directory.EnumerateFiles(path,"*.*", 
     SearchOption.AllDirectories) 
     .Where(s => s.EndsWith(".mp3") || s.EndsWith(".wma"))) 
     { 
      result.Add(file);     
     } 

它正常工作和做什麼，我需要的。除了一件小事。我想找到一個更好的方法來篩選多個擴展。我想用一個字符串數組與過濾器，如本：

string[] extensions = { "*.mp3", "*.wma", "*.mp4", "*.wav" }; 

什麼是最有效的方式做到這一點使用.NET框架4.0/LINQ？有什麼建議麼？

我想感謝所有幫助是一個偶然的程序員:-)

Answer 1

我創造了一些輔助方法這是我今年blogged約早期解決。

一個版本採用正則表達式\.mp3|\.mp4，另一個版本是字符串列表並且並行運行。

public static class MyDirectory 
{ // Regex version 
    public static IEnumerable<string> GetFiles(string path, 
         string searchPatternExpression = "", 
         SearchOption searchOption = SearchOption.TopDirectoryOnly) 
    { 
     Regex reSearchPattern = new Regex(searchPatternExpression, RegexOptions.IgnoreCase); 
     return Directory.EnumerateFiles(path, "*", searchOption) 
         .Where(file => 
           reSearchPattern.IsMatch(Path.GetExtension(file))); 
    } 

    // Takes same patterns, and executes in parallel 
    public static IEnumerable<string> GetFiles(string path, 
         string[] searchPatterns, 
         SearchOption searchOption = SearchOption.TopDirectoryOnly) 
    { 
     return searchPatterns.AsParallel() 
      .SelectMany(searchPattern => 
        Directory.EnumerateFiles(path, searchPattern, searchOption)); 
    } 
} 

Answer 2

從LINQ背景下剝離，這涉及到如何找出一個文件相匹配擴展名的列表。這裏比String.EndsWith()更好選擇System.IO.Path.GetExtension()。取決於集合，可以用.Contains()或.IndexOf()代替多個||。

var extensions = new HashSet<string>(StringComparer.OrdinalIgnoreCase) 
    { ".mp3", ".wma", ".mp4", ".wav" }; 

... s => extensions.Contains(Path.GetExtension(s)) 

Answer 3

string path = "C:\\"; 
var result = new List<string>(); 
string[] extensions = { ".mp3", ".wma", ".mp4", ".wav" }; 

foreach (string file in Directory.EnumerateFiles(path, "*.*", SearchOption.AllDirectories) 
    .Where(s => extensions.Any(ext => ext == Path.GetExtension(s)))) 
{ 
    result.Add(file); 
    Console.WriteLine(file); 
} 

Answer 4

我知道這是一箇舊帖子，但我想出了一個人們可能會喜歡使用的解決方案。

private IEnumerable<FileInfo> FindFiles() 
{ 
    DirectoryInfo sourceDirectory = new DirectoryInfo(@"C:\temp\mydirectory"); 
    string foldersFilter = "*bin*,*obj*"; 
    string fileTypesFilter = "*.mp3,*.wma,*.mp4,*.wav"; 

    // filter by folder name and extension 
    IEnumerable<DirectoryInfo> directories = foldersFilter.Split(',').SelectMany(pattern => sourceDirectory.EnumerateDirectories(pattern, SearchOption.AllDirectories)); 
    List<FileInfo> files = new List<FileInfo>(); 
    files.AddRange(directories.SelectMany(dir => fileTypesFilter.Split(',').SelectMany(pattern => dir.EnumerateFiles(pattern, SearchOption.AllDirectories)))); 

    // Pick up root files 
    files.AddRange(fileTypesFilter.Split(',').SelectMany(pattern => sourceDirectory.EnumerateFiles(fileTypesFilter, SearchOption.TopDirectoryOnly))); 

    // filter just by extension 
    IEnumerable<FileInfo> files2 = fileTypesFilter.Split(',').SelectMany(pattern => sourceDirectory.EnumerateFiles(pattern, SearchOption.AllDirectories)); 
} 

Answer 5

正如我在評論指出，雖然的Mikael史雲遜的助手方法是偉大的小的解決方案，如果你曾經嘗試再次做點事着急一次性項目，考慮的LINQ擴展。 Union（）。這允許您將兩個枚舉序列連接在一起。在你的情況下，代碼將如下所示：

List<string> result = Directory.EnumerateFiles(path,"*.mp3", SearchOption.AllDirectories) 
.Union(Directory.EnumerateFiles(path, ".wma", SearchOption.AllDirectories)).ToList(); 

這會在一行中創建並填充結果列表。

Answer 6

最優雅的方法可能是：

var directory = new DirectoryInfo(path); 
var masks = new[] { "*.mp3", "*.wav" }; 
var files = masks.SelectMany(directory.EnumerateFiles); 

但它未必是最有效的。

Answer 7

用於過濾使用相同的文件擴展名列表的字符串作爲GUI打開的對話框例如： -

".exe,.pdb".Split(',', ';', '|').SelectMany(_ => Directory.EnumerateFiles(".", "*" + _, searchOptions) 

打包：

public static IEnumerable<string> EnumerateFilesFilter(string path, string filesFilter, SearchOption searchOption = SearchOption.TopDirectoryOnly) 
    { 
     return filesFilter.Split(',', ';', '|').SelectMany(_ => Directory.EnumerateFiles(path, "*" + _, searchOption)); 
    }