码迷,mamicode.com
首页 > 其他好文 > 详细

LINQ和文件目录

时间:2020-03-04 00:20:52      阅读:96      评论:0      收藏:0      [点我收藏+]

标签:this   length   desktop   文件目录   比较   eth   string   use   equal   

记录https://docs.microsoft.com/zh-cn/dotnet/csharp/programming-guide/concepts/linq/linq-and-file-directories的学习

 

查询具有指定扩展名的文件 (SearchOption.AllDirectories 指递归文件夹获取所有文件)

string startFolder = @"C:\Users\bibi\Desktop\代码\异步\ConsoleApp4\Test\";
DirectoryInfo dir = new DirectoryInfo(startFolder);
IEnumerable<FileInfo> fileList = dir.GetFiles("*.*", SearchOption.AllDirectories);

var fileQuery = from file in fileList
                where file.Extension == ".png"
                orderby file.Name
                select file;

foreach(var item in fileQuery)
{
    Console.WriteLine(item.FullName);
}

按扩展名对文件进行分组

// Take a snapshot of the file system.  
string startFolder = @"C:\Users\bibi\Desktop\代码\异步\ConsoleApp4\Test\";

// Used in WriteLine to trim output lines.  
int trimLength = startFolder.Length;

// Take a snapshot of the file system.  
System.IO.DirectoryInfo dir = new System.IO.DirectoryInfo(startFolder);

// This method assumes that the application has discovery permissions  
// for all folders under the specified path.  
IEnumerable<System.IO.FileInfo> fileList = dir.GetFiles("*.*", System.IO.SearchOption.AllDirectories);

var queryGroupByExt = from file in fileList
                      group file by file.Extension.ToLower() into fileGroup
                      orderby fileGroup.Key
                      select fileGroup;

foreach(var group in queryGroupByExt)
{
    Console.WriteLine(group.Key);
    foreach(var item in group)
    {
        Console.WriteLine($"    {item.Name}");
    }
}

求目录下的所有文件的总字节数

string startFolder = @"C:\Users\bibi\Desktop\代码\异步\ConsoleApp4\Test\";

System.IO.DirectoryInfo dir = new System.IO.DirectoryInfo(startFolder);
var totalLength = dir.GetFiles().Sum(x=>x.Length);

Console.WriteLine(totalLength+" bytes");

对接文件夹中的文件(序列求等SequenceEqual、交集Insect、差集Except)

string pathA = @"C:\Users\bibi\Desktop\代码\异步\ConsoleApp4\Test\";
string pathB = @"C:\Users\bibi\Desktop\代码\异步\ConsoleApp4\Test\TestX\";

System.IO.DirectoryInfo dir1 = new System.IO.DirectoryInfo(pathA);
System.IO.DirectoryInfo dir2 = new System.IO.DirectoryInfo(pathB);

//使用了顶层目录SearchOption.TopDirectoryOnly,不需递归目录下的文件夹寻找文件,只要第一层文件。 IEnumerable
<System.IO.FileInfo> list1 = dir1.GetFiles("*.*", SearchOption.TopDirectoryOnly); IEnumerable<System.IO.FileInfo> list2 = dir2.GetFiles("*.*", SearchOption.TopDirectoryOnly); //使用自定义的文件默认比较器 FileCompare myFileCompare = new FileCompare(); //判断两个序列是否相等 bool isEqualOne = list1.SequenceEqual(list2, myFileCompare); if (isEqualOne == true) { Console.WriteLine("the two folders are the same"); } else { Console.WriteLine("The two folders are not the same"); } //求交集文件 var queryCommonFiles = list1.Intersect(list2, myFileCompare); if (queryCommonFiles.Any()) { Console.WriteLine("The following files are in both folders:"); foreach (var v in queryCommonFiles) { Console.WriteLine(v.FullName); //shows which items end up in result list } } //求差集文件 在list1却不在list2的文件 var queryList1Only = list1.Except(list2, myFileCompare); Console.WriteLine("The following files are in list1 but not list2:"); foreach (var v in queryList1Only) { Console.WriteLine(v.FullName); }

 

LINQ和文件目录

标签:this   length   desktop   文件目录   比较   eth   string   use   equal   

原文地址:https://www.cnblogs.com/bibi-feiniaoyuan/p/12405616.html

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!