package tablecloth-native

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A collection of unique values

A Set represents a collection of unique values.

Set is an immutable data structure which means operations like Set.add and Set.remove do not modify the data structure, but return a new set with the desired changes.

Since sets of ints and strings are so common the specialised Set.Int and Set.String modules are available which offer a convenient way to construct new sets.

Custom data types can be used with sets as long as the module satisfies the Comparator.S interface.

module Point = struct
  type t = int * int
  let compare = Tuple2.compare Int.compare Int.compare
  include Comparator.Make(struct
    type nonrec t = t
    let compare = compare
  end)
end

let points : Set.Of(Point).t = Set.fromList (module Points) [(0, 0); (3, 4); (6, 7)]

See the Comparator module for a more details.

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

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

Create

You can create a Set by providing a module conform to the Comparator.S signature by using empty, singleton, fromList or fromArray.

Specialised versions of the empty, singleton, fromList and fromArray functions available in the Set.Int and Set.String sub-modules.

val empty : (module Tablecloth__.TableclothComparator.S with type identity = 'identity and type t = 'a) -> ('a, 'identity) t

A set with nothing in it.

Often used as an initial value for functions like Array.fold

Examples

Array.fold 
  [|'m'; 'i'; 's'; 's'; 'i'; 's'; 's';'i';'p';'p';'i'|] 
  ~intial:(Set.empty (module Char))
  ~f:Set.add
|> Set.toArray
= [|'i'; 'm'; 'p'; 's'|]
val singleton : (module Tablecloth__.TableclothComparator.S with type identity = 'identity and type t = 'a) -> 'a -> ('a, 'identity) t

Create a set from a single Int

Examples

Set.singleton (module Int) 7 |> Set.toList = [7]
val fromArray : (module Tablecloth__.TableclothComparator.S with type identity = 'identity and type t = 'a) -> 'a array -> ('a, 'identity) t

Create a set from an Array

Examples

Set.fromArray (module String) [|"Ant"; "Bat"; "Bat"; "Goldfish"|] |> Set.toArray = [|"Ant";"Bat";"Goldfish"|]
val from_array : (module Tablecloth__.TableclothComparator.S with type identity = 'identity and type t = 'a) -> 'a array -> ('a, 'identity) t
val fromList : (module Tablecloth__.TableclothComparator.S with type identity = 'identity and type t = 'a) -> 'a list -> ('a, 'identity) t

Create a set from a List

Examples

Set.fromList (module Char) ['A'; 'B'; 'B'; 'G'] |> Set.toList = ['A';'B';'G']
val from_list : (module Tablecloth__.TableclothComparator.S with type identity = 'identity and type t = 'a) -> 'a list -> ('a, 'identity) t

Basic operations

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

Insert a value into a set.

Examples

Set.add (Set.Int.fromList [1; 2]) 3 |> Set.toList = [1; 2; 3]
Set.add (Set.Int.fromList [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.fromList [1; 2]) 2 |> Set.toList = [1]
let originalSet = Set.Int.fromList [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.fromList ["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.fromList ["Ant"; "Bat"; "Cat"] in

animals.Set.?{"Emu"} = false
val length : (_, _) t -> int

Determine the number of elements in a set.

Examples

Set.length (Set.Int.fromList [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.fromList [1; 3; 4; 8]) = Some 4
Set.find ~f:Int.isOdd (Set.Int.fromList [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 is_empty : (_, _) t -> bool
val any : ('value, _) t -> f:('value -> bool) -> bool

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

Examples

Set.any (Set.Int.fromArray [|2;3|]) ~f:Int.isEven = true
Set.any (Set.Int.fromList [1;3]) ~f:Int.isEven = false
Set.any (Set.Int.fromList []) ~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.fromArray [|2;4|]) = true
Set.all ~f:Int.isEven (Set.Int.fromLis [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.fromList [1;2;5]) (Set.Int.fromList [2;3;4]) |> Set.toList = [1;5]
Set.difference (Set.Int.fromList [2;3;4]) (Set.Int.fromList [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.fromList [1;2;5]) (Set.Int.fromList [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.fromList [1;2;5]) (Set.Int.fromList [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.fromList [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.fromList [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.fromList [1;2;3;4]) = 24
val forEach : ('a, _) t -> f:('a -> unit) -> unit

Runs a function f against each element of the set.

val for_each : ('a, _) t -> f:('a -> unit) -> unit

Convert

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

Converts a set into an Array

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

Converts a set into a List.

val to_list : ('a, _) t -> '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