幫我解析一個文本文件並提取具體的值

Question

我有一個文件叫lijst.txt。該文件是來自printmessage事件日誌文件的輸出。 所有行都具有相同的格式。 我想從每行中提取用戶名，該用戶名位於單詞owned by和was之間。另外，我想提取位於pages printed:和.之間的pagecount。我想將這些值放在一個新的文本文件中。

問候，

丹尼斯（新在F＃）

Answer 1

我會建議使用正則表達式這一點，是這樣的：

open System.Text.RegularExpressions 

let usernameRegex = new Regex(".*owned by\s+(?<username>.*)\s+was.*") 

/// Trys to extract the username from a given line of text. Returns None if the line is malformed 
// Note: You could also use failwith in the else branch or throw an exception or ... 
let extractUsername line = 
    let regexMatch = usernameRegex.Match(line) in 
    if regexMatch.Success then Some regexMatch.Groups.["username"].Value else None 

// In reality you would like to load this from file using File.ReadAllLines 
let sampleLines = 
    ["Some text some text owned by DESIRED USERNAME was some text some text"; 
    "Some text line not containing the pattern"; 
    "Another line owned by ANOTHER USER was"] 

let extractUsernames lines = 
    lines 
    |> Seq.map extractUsername 
    |> Seq.filter (fun usernameOption -> usernameOption.IsSome) 
    |> Seq.map (fun usernameOption -> usernameOption.Value) 

// You can now save the usernames to a file using 
// File.WriteAllLines("FileName", extractUsernames(sampleLines)) 

Answer 2

你可以這樣做：

let getBetween (a:string) (b:string) (str:string) = 
     str.Split(a.ToCharArray()).[1].Split(b.ToCharArray()).[0].Trim() 

let total (a:string seq) = 
    (a |> Seq.map Int32.Parse |> Seq.reduce (+)).ToString() 

File.ReadAllLines("inFile") |> Seq.map (fun l -> (getBetween "owned by" "was" l , getBetween "Pages printed:" "." l)) 
|> Seq.groupBy (fun (user,count) -> user) 
|> Seq.map (fun (user,counts) -> user + "\t" + (counts |> Seq.map snd |> total)) 
|> (fun s -> File.WriteAllLines("outFile",s))