while循環中的多個foreach循環

Question

是否有可能在任何循環結構中包含多個「foreach」語句，如while或for ...我想同時打開兩個不同目錄中的.wav文件，以便我可以比較來自兩者的文件。 這裏是我想這樣做，但它肯定是錯誤的..在這方面的任何幫助表示讚賞。

string[] fileEntries1 = Directory.GetFiles(folder1, "*.wav"); 
string[] fileEntries2 = Directory.GetFiles(folder11, "*.wav"); 
while (foreach(string fileName1 in fileEntries1) && foreach(string fileName2 in fileEntries2)) 

Answer 1

像這樣的事情，因爲你只需要驗證相同的文件名：

IEnumerable<string> fileEntries1 = Directory.GetFiles(folder1, "*.wav").Select(x => Path.GetFileName(x)); 
IEnumerable<string> fileEntries2 = Directory.GetFiles(folder2, "*.wav").Select(x => Path.GetFileName(x)); 

IEnumerable<string> filesToIterate = (fileEntries1.Count() > fileEntries2.Count()) ? fileEntries1 : fileEntries2; 
IEnumerable<string> filesToValidate = (fileEntries1.Count() < fileEntries2.Count()) ? fileEntries1 : fileEntries2; 

// Iterate the bigger collection 
foreach (string fileName in filesToIterate) 
{ 
    // Find the files in smaller collection 
    if (filesToValidate.Contains(fileName)) 
    { 
     // Get actual file and compare 
    } 
    else 
    { 
     // File does not exist in another list. Handle appropriately 
    } 
} 

NET 2.0基礎的解決方案：

List<string> fileEntries1 = new List<string>(Directory.GetFiles(folder1, "*.wav")); 

List<string> fileEntries2 = new List<string>(Directory.GetFiles(folder2, "*.wav")); 

List<string> filesToIterate = (fileEntries1.Count > fileEntries2.Count) ? fileEntries1 : fileEntries2; 
filesToValidate = (fileEntries1.Count < fileEntries2.Count) ? fileEntries1 : fileEntries2; 

string iteratorFileName; 
string validatorFilePath; 

// Iterate the bigger collection 
foreach (string fileName in filesToIterate) 
{ 
    iteratorFileName = Path.GetFileName(fileName); 

    // Find the files in smaller collection 
    if ((validatorFilePath = FindFile(iteratorFileName)) != null) 
    { 
     // Compare fileName and validatorFilePath files here 
    } 
    else 
    { 
     // File does not exist in another list. Handle appropriately 
    } 
} 

FindFile方法：

static List<string> filesToValidate; 

private static string FindFile(string fileToFind) 
{ 
    string returnValue = null; 

    foreach (string filePath in filesToValidate) 
    { 
     if (string.Compare(Path.GetFileName(filePath), fileToFind, true) == 0) 
     { 
      // Found the file 
      returnValue = filePath; 
      break; 
     } 
    } 

    if (returnValue != null) 
    { 
     // File was found in smaller list. Remove this file from the list since we do not need to look for it again 
     filesToValidate.Remove(returnValue);  
    } 

    return returnValue;  
} 

根據您的需要，您可能會也可能不會選擇靜態字段和方法。

Answer 2

如果要分別在兩個路徑中迭代所有文件對，可以按如下所示進行操作。

string[] fileEntries1 = Directory.GetFiles(folder1, "*.wav"); 
string[] fileEntries2 = Directory.GetFiles(folder11, "*.wav"); 

foreach(string fileName1 in fileEntries1) 
{ 
    foreach(string fileName2 in fileEntries2) 
    { 
     // to the actual comparison 
    } 
} 

Answer 3

這是我的建議，使用LINQ

using System.Linq; 

var fileEntries1 = Directory.GetFiles(folder1, "*.wav"); 
var fileEntries2 = Directory.GetFiles(folder11, "*.wav"); 
foreach (var entry1 in fileEntries1) 
{ 
    var entries = fileEntries2.Where(x => Equals(entry1, x)); 
    if (entries.Any()) 
    { 
     //We have matches 
     //entries is a list of matches in fileentries2 for entry1 
    } 
} 

Answer 4

Gramatically說沒有。這是因爲foreach構造是陳述而while陳述中的測試必須是表達式。

你最好的賭注是嵌套foreach塊：

foreach(string fileName1 in fileEntries1) 
{ 
    foreach(string fileName2 in fileEntries2) 

Answer 5

如果要啓用「並聯」兩個集合，然後用自己的迭代器是這樣的：

var fileEntriesIterator1 = Directory.EnumerateFiles(folder1, "*.wav").GetEnumerator(); 
var fileEntriesIterator2 = Directory.EnumerateFiles(folder11, "*.wav").GetEnumerator(); 

while(fileEntriesIterator1.MoveNext() && fileEntriesIterator2.MoveNext()) 
{ 
    var file1 = fileEntriesIterator1.Current; 
    var file2 = fileEntriesIterator2.Current; 
} 

如果一個集合是比其他較短，這種循環會更短的收集有沒有更多的時候結束元素。

Answer 6

我喜歡這種類型的陳述在一行中。所以即使這裏的大部分答案都是正確的，我也會給你這個答案。

string[] fileEntries1 = Directory.GetFiles(folder1, "*.wav"); 
string[] fileEntries2 = Directory.GetFiles(folder11, "*.wav"); 

foreach(var fileExistsInBoth in fileEntries1.Where(fe1 => fileEntries2.Contains(fe1)) 
{ 
    /// here you will have the records which exists in both of the lists 
}