如何使用F＃获取最新的x目录文件夹条目

Question

我被困在试图找出使用F＃获取特定根目录中最新的n个文件夹的方法。以下代码是该旅程的结果，我想在此发布并分享代码示例以帮助其他工程师尝试解决类似问题。

open System 
open System.IO 

// only get the N latest FOLDERS in a directory  
let getLatestNFolders (rootDirectory:string) (howmany:int) = 
    let latestFolders = 
     Directory.GetDirectories(rootDirectory) 
     |> Seq.cache 
     |> Seq.map(fun filePath -> (filePath, Directory.GetCreationTime(filePath))) 
     |> Seq.sortBy(fun (path, time) -> -time.Ticks) // descending order 
     |> Seq.take(howmany) 
     |> Seq.map(fun (path, time) -> path) 
     |> Set.ofSeq 
    latestFolders 

let results = getLatestNFolders "c:\\temp" 3 

results |> Seq.iter(fun path -> printfn "%s\n" path) 

Answer 1

这里有一些改进，主要集中在去除一些多余的内容：

// only get the N latest FOLDERS in a directory  
let getLatestNFolders (rootDirectory:string) howmany = 
    Directory.GetDirectories(rootDirectory) 
    |> Seq.sortBy(fun path -> -Directory.GetCreationTime(path).Ticks) // descending order 
    |> Seq.take howmany