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Matrix

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(* Transposes rectangular matrices *)
let transpose matrix =
    let rec fetch_column acc (matr:(int list list)) = (* Makes a column list from a row list *)
        if matr.Head.Length = 0 then (List.rev acc) (* Stop *)
        else fetch_column
                ([for row in matr -> row.Head]::acc) (* Fetches the first item from each row *)
                (List.map (fun row -> match row with [] -> [] | h::t -> t) matr)
    fetch_column [] matrix

transpose [[1;2;3;4];[5;6;7;8];[9;10;11;12]]

val transpose : matrix:int list list -> int list list

Full name: Script.transpose

val matrix : int list list

val fetch_column : (int list list -> int list list -> int list list)

val acc : int list list

val matr : int list list

Multiple items
val int : value:'T -> int (requires member op_Explicit)

Full name: Microsoft.FSharp.Core.Operators.int

--------------------
type int = int32

Full name: Microsoft.FSharp.Core.int

--------------------
type int<'Measure> = int

Full name: Microsoft.FSharp.Core.int<_>

type 'T list = List<'T>

Full name: Microsoft.FSharp.Collections.list<_>

property List.Head: int list

property List.Length: int

Multiple items
module List

from Microsoft.FSharp.Collections

--------------------
type List<'T> =
  | ( [] )
  | ( :: ) of Head: 'T * Tail: 'T list
  interface IEnumerable
  interface IEnumerable<'T>
  member Head : 'T
  member IsEmpty : bool
  member Item : index:int -> 'T with get
  member Length : int
  member Tail : 'T list
  static member Cons : head:'T * tail:'T list -> 'T list
  static member Empty : 'T list

Full name: Microsoft.FSharp.Collections.List<_>

val rev : list:'T list -> 'T list

Full name: Microsoft.FSharp.Collections.List.rev

val row : int list

property List.Head: int

val map : mapping:('T -> 'U) -> list:'T list -> 'U list

Full name: Microsoft.FSharp.Collections.List.map

val h : int

val t : int list

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More information

Link:	http://fssnip.net/aD
Posted:	12 years ago
Author:	Matrix
Tags:	matrix