WideFinder--Naive F# Implementation

Scott Hanselman's Computer Zen - The Weekly Source Code 9 - WideFinder Edition

Scott Hanselman's Computer Zen - The Weekly Source Code 9 - WideFinder Edition — Tue, 23 Oct 2007 08:24:24 GMT

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The Weekly Source Code 9 - WideFinder Edition

ASPInsiders — Tue, 23 Oct 2007 08:45:15 GMT

In my new ongoing quest to read source code to be a better developer , I now present the ninth in an

re: WideFinder--Naive F# Implementation

JHugard — Tue, 23 Oct 2007 20:58:09 GMT

Don't forget to add "take the top 10" and "print to stdout":

#light

open System.Text.RegularExpressions

open System.IO

open System.Text

let regex = new Regex(@"GET /ongoing/When/\d\d\dx/(\d\d\d\d/\d\d/\d\d/[^ .]+)", RegexOptions.Compiled)

let seqRead fileName =

seq { use reader = new StreamReader(File.OpenRead(fileName))

while not reader.EndOfStream do

yield reader.ReadLine() }

let query fileName =

seqRead fileName

|> Seq.map (fun line -> regex.Match(line))

|> Seq.filter (fun regMatch -> regMatch.Success)

|> Seq.map (fun regMatch -> regMatch.Value)

|> Seq.countBy (fun url -> url)

|> Seq.take 10

for result in query @"file.txt" do

let url, count = result

printfn "%A - %A" url count

re: WideFinder--Naive F# Implementation

Tony Nassar — Fri, 07 Dec 2007 07:33:44 GMT

I enjoy your blog, and it's helped inspire me to learn F#. Since it's hard to introduce it into production code (my colleagues, and the build machine, would have to have F# installed), I'm using it for one-off scripts. Wow, it's strange to be using a REPL again! Anyway, I have to munge through text files, and would recommend Seq.generate_using for that purpose:

let lines = Seq.generate_using (fun () -> File.OpenText(@"solveBatch.Cplex.txt"))

(fun (stream : StreamReader) -> match stream.ReadLine() with | null -> None | line -> Some line);;

That took me about 30 minutes to get right. It would have been faster to cut and paste, but in the end I learned something.