C#练习题答案: 在目录中查找文件【难度：2级】--景越C#经典编程题库,1000道C#基础练习题等你来挑战

最新推荐文章于 2021-12-25 21:58:34 发布

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本文提供了10种不同的C#代码示例，展示了如何在目录结构中递归查找特定文件的方法。这些示例涵盖了从简单遍历到利用LINQ进行复杂筛选的多种技术。

在目录中查找文件【难度:2级】:

答案1:

using System;
using System.Linq;
using System.Collections.Generic;
public class Search
    {
        public static string FindFileInFolder(Folder folder, String fileName)
        {
            if (folder.Items.Select(x=>x.Name).Contains(fileName)) return folder.Name+"\\"+fileName;
            return folder.Name+"\\"+folder.Items.OfType<Folder>().Select(x=>FindFileInFolder(x,fileName)).First(x=>x.Contains(fileName));
        }
    }

答案2:

using System;
using System.Linq;

public class Search
    {
        public static string FindFileInFolder(Folder folder, String fileName)
        {
            var foundFolder = folder.Items.FirstOrDefault(x => x.Name == fileName);
            if (foundFolder !=null)
            {
                return folder.Name +"\\" +fileName;
            }
            var folders = folder.Items.Where(x => (x as Folder) != null).Cast<Folder>().ToList();
            if (folders.Count == 0)
            {
                return null;
            }
            return folder.Name + "\\" + folders.Select(f => FindFileInFolder(f, fileName)).First(x => x != null);
        }
    }

答案3:

using System;
using System.Collections.Generic;
public class Search
    {
        public static string FindFileInFolder(Folder folder, String fileName)
        {
            foreach(Item item in folder.Items)
            {
                if(item.GetType().ToString() == "File")
                {
                    if(item.Name == fileName)
                    {
                        return folder.Name + "\\" + fileName;
                    }
                }
                else
                {
                    var x = FindFileInFolder((Folder)item, fileName);
                    if(x.Length > 0)
                    {
                        return folder.Name + "\\" + x;
                    }
                }
            }
            return "";
        }
    }

答案4:

using System.Collections.Generic;
public class Search
{
    public static string FindFileInFolder(Folder folder, string fileName, string path = "")
    {
        if (path == "") path = folder.Name;
        foreach (var file in folder.Items)
        {
            if (file.Name == fileName) return path + "\\" + fileName;
            if (file is Folder) return FindFileInFolder(file as Folder, fileName, path + "\\" + file.Name);
        }
        return "Not Found";
    }
}

答案5:

using System;

public class Search
{
  public static string FindFileInFolder(Folder folder, String fileName)
  {
    foreach(var item in folder.Items)
    {
      if(item is File f &amp;&amp; f.Name == fileName)
        return $"{folder.Name}\\{fileName}";
        
      if(item is Folder fol)
      {
        var result = FindFileInFolder(fol, fileName);
        if(result != null)
          return $"{folder.Name}\\{result}";
      }
    }
    return null;  
  }
}

答案6:

using System;

public class Search
{
  public static string FindFileInFolder(Folder folder, String fileName)
  {
    string address = folder.Name + "\\";
    foreach(Item i in folder.Items)
    {
      if(i is File) 
      {
        if(i.Name == fileName) 
        {
          address += i.Name;
          break;
        }
      }
      else 
      {
        address += FindFileInFolder((Folder)i, fileName);
        break;
      } 
    }
    return address;
  }
}

答案7:

using System;
using System.Linq;
using System.Collections.Generic;
 public class Search
    {
        public static string FindFileInFolder(Folder folder, String fileName)
        {
            string res = "";
            res = Droga(folder, fileName, res);
            return res;
        }
        public static string Droga(Folder folder, String fileName, string res)
        {
            res += folder.Name + "\\";
            if (folder.Items.Where(x => x.GetType() == typeof(File)).Any(x => x.Name.Equals(fileName))) return res += fileName;
            return Droga((Folder)folder.Items.First(x => x.GetType() == typeof(Folder)), fileName, res);
        }
    }

答案8:

using System;

public class Search
    {
        public static string FindFileInFolder(Folder folder, String fileName)
        {
            foreach(Item item in folder.Items)
            {
              if(item.Name == fileName)
                return folder.Name + "\\" + fileName;
              if(item is Folder)
              {
                string path = FindFileInFolder((Folder)item, fileName);
                if(path != "")
                  return folder.Name + "\\" + path;
              }
            }
          return "";
        }
    }

答案9:

using System;
using System.Linq;
using System.Collections.Generic;

public class Search
    {
        public static string FindFileInFolder(Folder folder, String fileName)
        {
            var path = folder.Name;
            var currentFolder = folder;
            var found = false;

            while (!found &amp;&amp; currentFolder != null)
            {
                File fileResult = currentFolder.Items?.FirstOrDefault(i => i.Name == fileName) as File;

                if (fileResult != null)
                {
                    path += $"\\{fileResult.Name}";
                    found = true;
                }
                else
                {
                    currentFolder = currentFolder.Items?.FirstOrDefault(i => i is Folder) as Folder;
                    path += $"\\{currentFolder?.Name}";
                }
            }

            return path;
        }
    }

答案10:

using System;
using System.Collections.Generic;
using System.Linq;

public class Search
    {
        public static string FindFileInFolder(Folder folder, String fileName)
        {
            var path = folder.Name;
            var currentFolder = folder;
            var found = false;

            while (!found &amp;&amp; currentFolder != null)
            {
                File fileResult = currentFolder.Items?.FirstOrDefault(i => i.Name == fileName) as File;

                if (fileResult != null)
                {
                    path += $"\\{fileResult.Name}";
                    found = true;
                }
                else
                {
                    currentFolder = currentFolder.Items?.FirstOrDefault(i => i is Folder) as Folder;
                    path += $"\\{currentFolder?.Name}";
                }
            }

            return path;
        }
    }