Implement a suppression list

Take a sequence and exclude values from it based on another 'suppression list' sequence.

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module Suppress

// Returns a sequence which consists of the items from 'values' for which
// no item in 'unwanted' gives true when passed to function (f valueItem unwantedItem).
let suppressBy (f : 'T -> 'U -> bool) (values : seq<'T>) (unwanted : seq<'U>) =
    values
    |> Seq.filter (fun v -> unwanted |> Seq.exists (fun u -> f v u) |> not)

// [0; 1; 2; 5; 6; 7; 8; 9]
let example =
    suppressBy (=) [0..9] [3; 4] |> List.ofSeq

type Prospect = { name : string; phoneNumber: string }
type TPSRecord = { phoneNumber: string }

let prospects = [ {name = "A Smith"; phoneNumber = "01234 56789"}
                  {name = "B Smith"; phoneNumber = "01234 56710"}
                  {name = "C Smith"; phoneNumber = "01234 56711"} ]

let tpsData = [ {phoneNumber = "01234 56710"}
                {phoneNumber = "01234 56712"} ]

// [{name = "A Smith"; phoneNumber = "01234 56789";}
//  {name = "C Smith"; phoneNumber = "01234 56711";}]
let doTpsSuppression =
    prospects |> suppressBy (fun p s -> p.phoneNumber = s.phoneNumber) tpsData
    |> List.ofSeq

module Suppress

val suppressBy : f:('T -> 'U -> bool) -> values:seq<'T> -> unwanted:seq<'U> -> seq<'T>

Full name: Suppress.suppressBy

val f : ('T -> 'U -> bool)

type bool = System.Boolean

Full name: Microsoft.FSharp.Core.bool

val values : seq<'T>

Multiple items
val seq : sequence:seq<'T> -> seq<'T>

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

--------------------
type seq<'T> = System.Collections.Generic.IEnumerable<'T>

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

val unwanted : seq<'U>

module Seq

from Microsoft.FSharp.Collections

val filter : predicate:('T -> bool) -> source:seq<'T> -> seq<'T>

Full name: Microsoft.FSharp.Collections.Seq.filter

val v : 'T

val exists : predicate:('T -> bool) -> source:seq<'T> -> bool

Full name: Microsoft.FSharp.Collections.Seq.exists

val u : 'U

val not : value:bool -> bool

Full name: Microsoft.FSharp.Core.Operators.not

val example : int list

Full name: Suppress.example

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 ofSeq : source:seq<'T> -> 'T list

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

type Prospect =
{name: string;
phoneNumber: string;}

Full name: Suppress.Prospect

Prospect.name: string

Multiple items
val string : value:'T -> string

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

--------------------
type string = System.String

Full name: Microsoft.FSharp.Core.string

Prospect.phoneNumber: string

type TPSRecord =
{phoneNumber: string;}

Full name: Suppress.TPSRecord

TPSRecord.phoneNumber: string

val prospects : Prospect list

Full name: Suppress.prospects

val tpsData : TPSRecord list

Full name: Suppress.tpsData

val doTpsSuppression : TPSRecord list

Full name: Suppress.doTpsSuppression

val p : TPSRecord

val s : Prospect

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More information

Link:	http://fssnip.net/fx
Posted:	12 years ago
Author:	Kit Eason
Tags:	sequences