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Helper F# script file for working with csv files
open System.IO
open Microsoft.FSharp.Reflection
open System
type Array =
static member join delimiter xs =
xs
|> Array.map (fun x -> x.ToString())
|> String.concat delimiter
type Seq =
static member write (path:string) (data:seq<'a>): unit =
use writer = new StreamWriter(path)
data
|> Seq.iter writer.WriteLine
static member toCsv (separator:string) (useEnclosure:bool) (headerMapping:string -> string) (data:seq<'a>) =
seq {
let dataType = typeof<'a>
let stringSeqDataType = typeof<System.Collections.Generic.IEnumerable<string>>
let inline enclose s =
match useEnclosure with
| true -> "\"" + (string s) + "\""
| false -> string s
let header =
match dataType with
| ty when FSharpType.IsRecord ty ->
FSharpType.GetRecordFields dataType
|> Array.map (fun info -> headerMapping info.Name)
| ty when FSharpType.IsTuple ty ->
FSharpType.GetTupleElements dataType
|> Array.mapi (fun idx info -> headerMapping(string idx) )
| ty when ty.IsAssignableFrom stringSeqDataType ->
data :?> seq<seq<string>> |> Seq.head
|> Seq.toArray
| _ -> dataType.GetProperties()
|> Array.map (fun info -> headerMapping info.Name)
yield header |> Array.map enclose |> Array.join separator
let lines =
match dataType with
| ty when FSharpType.IsRecord ty ->
data |> Seq.map FSharpValue.GetRecordFields
| ty when FSharpType.IsTuple ty ->
data |> Seq.map FSharpValue.GetTupleFields
| ty when ty.IsAssignableFrom stringSeqDataType ->
data :?> seq<seq<string>> |> Seq.tail
|> Seq.map (fun ss -> Seq.toArray ss |> Array.map (fun s -> s :> obj) )
| _ ->
let props = dataType.GetProperties()
data |> Seq.map ( fun line ->
props |> Array.map ( fun prop ->
prop.GetValue(line, null) ))
|> Seq.map (Array.map enclose)
yield! lines |> Seq.map (Array.join separator)
}
static member read (path:string) =
seq {
use reader = new StreamReader(path)
let mutable valid = true
while(valid) do
let line = reader.ReadLine()
if(isNull line) then
valid <- false
else
yield line
}
static member fromCsv<'a> (separator:string) (removeEnclosure:bool) (headerMapping:string -> string) (valueMapping:string -> string -> obj) (lines:seq<string>) : seq<'a> =
let dataType = typeof<'a>
let extract(gd:Map<string,string>) =
let flds = FSharpType.GetRecordFields(dataType)
let vals = [| for f in flds -> (valueMapping f.Name gd.[f.Name]) |]
FSharpValue.MakeRecord(dataType, vals) :?> 'a
let split (s:string) (l:string) = l.Split([|s|], StringSplitOptions.None)
let inline unenclose (s:string) =
match removeEnclosure with
| true ->
match s with
| "\"" -> ""
| "\"\"" -> ""
| s when s.StartsWith("\"") && s.EndsWith("\"") -> s.Substring(1, s.Length - 2)
| s when s.StartsWith("\"") -> s.Substring(1, s.Length - 1)
| s when s.EndsWith("\"") -> s.Substring(0, s.Length - 2)
| false -> s
let propNames = lines |> Seq.head |> split separator |> Array.map (unenclose >> headerMapping)
let data = lines
|> Seq.tail
|> Seq.map (fun l -> l |> split separator |> Array.zip propNames |> Map.ofArray |> extract)
data
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