package reason-standard

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Module Standard.Set

A collection of unique values

type ('a, 'id) t
module Of (M : sig ... end) : sig ... end

This functor lets you describe the type of Maps a little more concisely.

Create

A Set can be constructed using one of the specialised functions available in the Set.Int, Set.String or Set.Poly sub-modules.

You can create sets of custom data types which conform to the Comparator.S signature by using empty, singleton, ofList or ofArray.

val empty : (module Standard__.Core.Comparator.S with type identity = 'identity and type t = 'a) -> ('a, 'identity) t

A set with nothing in it.

val singleton : (module Standard__.Core.Comparator.S with type identity = 'identity and type t = 'a) -> 'a -> ('a, 'identity) t

Create a set from a single Int

Examples

Set.Int.singleton 5 |> Set.toList = [5]
val ofArray : (module Standard__.Core.Comparator.S with type identity = 'identity and type t = 'a) -> 'a array -> ('a, 'identity) t

Create a set from an Array

Examples

Set.Int.ofArray [|1;2;3;3;2;1;7|] |> Set.toArray = [|1;2;3;7|]
val ofList : (module Standard__.Core.Comparator.S with type identity = 'identity and type t = 'a) -> 'a list -> ('a, 'identity) t

Create a set from a List

Examples

Set.Int.ofList [1;2;3;3;2;1;7] |> Set.toList = [1;2;3;7]

Basic operations

val add : ('a, 'id) t -> 'a -> ('a, 'id) t

Insert a value into a set.

Examples

Set.add (Set.Int.ofList [1; 2]) 3 |> Set.toList = [1; 2; 3]
Set.add (Set.Int.ofList [1; 2]) 2 |> Set.toList = [1; 2]
val remove : ('a, 'id) t -> 'a -> ('a, 'id) t

Remove a value from a set, if the set doesn't contain the value anyway, returns the original set

Examples

Set.remove (Set.Int.ofList [1; 2]) 2 |> Set.toList = [1]
  let originalSet = Set.Int.ofList [1; 2] in
  let newSet = Set.remove orignalSet 3 in
  originalSet = newSet
val includes : ('a, _) t -> 'a -> bool

Determine if a value is in a set

Examples

Set.includes (Set.String.ofList ["Ant"; "Bat"; "Cat"]) "Bat" = true
val (.?{}) : ('element, _) t -> 'element -> bool

The index operator version of includes

Note Currently this is only supported by the OCaml syntax.

Examples

  let animals = Set.String.ofList ["Ant"; "Bat"; "Cat"] in
  numbers.Set.?{"Emu"} = false
val length : (_, _) t -> int

Determine the number of elements in a set.

Examples

Set.length (Set.Int.ofList [1; 2; 3]) = 3
val find : ('value, _) t -> f:('value -> bool) -> 'value option

Returns, as an Option, the first element for which f evaluates to true. If f doesn't return true for any of the elements find will return None.

Examples

Set.find ~f:Int.isEven (Set.Int.ofList [1; 3; 4; 8]) = Some 4
Set.find ~f:Int.isOdd (Set.Int.ofList [0; 2; 4; 8]) = None
Set.find ~f:Int.isEven Set.Int.empty = None

Query

val isEmpty : (_, _) t -> bool

Check if a set is empty.

Examples

Set.isEmpty (Set.Int.empty) = true
Set.isEmpty (Set.Int.singleton 4) = false
val any : ('value, _) t -> f:('value -> bool) -> bool

Determine if f returns true for any values in a set.

Examples

Set.any (Set.Int.ofArray [|2;3|]) ~f:Int.isEven = true
Set.any (Set.Int.ofList [1;3]) ~f:Int.isEven = false
Set.any (Set.Int.ofList []) ~f:Int.isEven = false
val all : ('value, _) t -> f:('value -> bool) -> bool

Determine if f returns true for all values in a set.

Examples

Set.all ~f:Int.isEven (Set.Int.ofArray [|2;4|]) = true
Set.all ~f:Int.isEven (Set.Int.ofLis [2;3]) = false
Set.all ~f:Int.isEven Set.Int.empty = true

Combine

val difference : ('a, 'id) t -> ('a, 'id) t -> ('a, 'id) t

Returns a new set with the values from the first set which are not in the second set.

Examples

Set.difference (Set.Int.ofList [1;2;5]) (Set.Int.ofList [2;3;4]) |> Set.toList = [1;5]
Set.difference (Set.Int.ofList [2;3;4]) (Set.Int.ofList [1;2;5]) |> Set.toList = [3;4]
val intersection : ('a, 'id) t -> ('a, 'id) t -> ('a, 'id) t

Get the intersection of two sets. Keeps values that appear in both sets.

Examples

Set.intersection (Set.Int.ofList [1;2;5]) (Set.Int.ofList [2;3;4]) |> Set.toList= [2]
val union : ('a, 'id) t -> ('a, 'id) t -> ('a, 'id) t

Get the union of two sets. Keep all values.

Examples

Set.union (Set.Int.ofList [1;2;5]) (Set.Int.ofList [2;3;4]) |> Set.toList = [1;2;3;4;5]

Transform

val filter : ('a, 'id) t -> f:('a -> bool) -> ('a, 'id) t

Keep elements that f returns true for.

Examples

Set.filter (Set.Int.ofList [1;2;3]) ~f:Int.isEven |> Set.toList = [2]
val partition : ('a, 'id) t -> f:('a -> bool) -> ('a, 'id) t * ('a, 'id) t

Divide a set into two according to f. The first set will contain the values that f returns true for, values that f returns false for will end up in the second.

Examples

  let numbers = Set.Int.ofList [1; 1; 5; 6; 5; 7; 9; 8] in
  let (evens, odds) = Set.partition numbers ~f:Int.isEven in
  Set.toList evens = [6; 8]
  Set.toList odds = [1; 5; 7; 9]
val fold : ('a, _) t -> initial:'b -> f:('b -> 'a -> 'b) -> 'b

Transform a set into a value which is result of running each element in the set through f, where each successive invocation is supplied the return value of the previous.

See Array.fold for a more in-depth explanation.

Examples

Set.fold ~f:( * ) ~initial:1 (Set.Int.ofList [1;2;3;4]) = 24
val forEach : ('a, _) t -> f:('a -> unit) -> unit

Runs a function f against each element of the set.

Convert

val toArray : ('a, _) t -> 'a array

Converts a set into an Array

val toList : ('a, _) t -> 'a list

Converts a set into a List.

module Poly : sig ... end

Construct sets which can hold any data type using the polymorphic compare function.

module Int : sig ... end

Construct sets of Ints

module String : sig ... end

Construct sets of Strings