Module Core_kernel.Array

This module extends Base.Array.

The Array type

type 'a t = 'a Base.Array.t
include Bin_prot.Binable.S1 with type 'a t := 'a t
val bin_shape_t : Bin_prot.Shape.t -> Bin_prot.Shape.t
val bin_size_t : ('a, 'a t) Bin_prot.Size.sizer1
val bin_write_t : ('a, 'a t) Bin_prot.Write.writer1
val bin_read_t : ('a, 'a t) Bin_prot.Read.reader1
val __bin_read_t__ : ('a, int -> 'a t) Bin_prot.Read.reader1
val bin_writer_t : ('a, 'a t) Bin_prot.Type_class.S1.writer
val bin_reader_t : ('a, 'a t) Bin_prot.Type_class.S1.reader
val bin_t : ('a, 'a t) Bin_prot.Type_class.S1.t
include Typerep_lib.Typerepable.S1 with type 'a t := 'a t
val typerep_of_t : 'a Typerep_lib.Std_internal.Typerep.t -> 'a t Typerep_lib.Std_internal.Typerep.t
val typename_of_t : 'a Typerep_lib.Typename.t -> 'a t Typerep_lib.Typename.t

The signature included from Base.Array

include module type of struct include Base.Array end with type 'a t := 'a t
val compare : ('a -> 'a -> int) -> 'a t -> 'a t -> int
include Base.Sexpable.S1 with type 'a t := 'a t
val t_of_sexp : (Sexplib0.Sexp.t -> 'a) -> Sexplib0.Sexp.t -> 'a t
val sexp_of_t : ('a -> Sexplib0.Sexp.t) -> 'a t -> Sexplib0.Sexp.t
val t_sexp_grammar : Base.Sexp.Private.Raw_grammar.t
include Base.Binary_searchable.S1 with type 'a t := 'a t
val binary_search_segmented : ?pos:int -> ?len:int -> 'a t -> segment_of:('a -> [ `Left | `Right ]) -> [ `Last_on_left | `First_on_right ] -> int option
include Base.Container.S1 with type 'a t := 'a t
val mem : 'a t -> 'a -> equal:('a -> 'a -> bool) -> bool

Checks whether the provided element is there, using equal.

val length : 'a t -> int
val is_empty : 'a t -> bool
val iter : 'a t -> f:('a -> unit) -> unit
val fold : 'a t -> init:'accum -> f:('accum -> 'a -> 'accum) -> 'accum

fold t ~init ~f returns f (... f (f (f init e1) e2) e3 ...) en, where e1..en are the elements of t

val fold_result : 'a t -> init:'accum -> f:('accum -> 'a -> ('accum, 'e) Base.Result.t) -> ('accum, 'e) Base.Result.t

fold_result t ~init ~f is a short-circuiting version of fold that runs in the Result monad. If f returns an Error _, that value is returned without any additional invocations of f.

val fold_until : 'a t -> init:'accum -> f:('accum -> 'a -> ('accum, 'final) Base__Container_intf.Export.Continue_or_stop.t) -> finish:('accum -> 'final) -> 'final

fold_until t ~init ~f ~finish is a short-circuiting version of fold. If f returns Stop _ the computation ceases and results in that value. If f returns Continue _, the fold will proceed. If f never returns Stop _, the final result is computed by finish.

Example:

type maybe_negative =
  | Found_negative of int
  | All_nonnegative of { sum : int }

(** [first_neg_or_sum list] returns the first negative number in [list], if any,
    otherwise returns the sum of the list. *)
let first_neg_or_sum =
  List.fold_until ~init:0
    ~f:(fun sum x ->
      if x < 0
      then Stop (Found_negative x)
      else Continue (sum + x))
    ~finish:(fun sum -> All_nonnegative { sum })
;;

let x = first_neg_or_sum [1; 2; 3; 4; 5]
val x : maybe_negative = All_nonnegative {sum = 15}

let y = first_neg_or_sum [1; 2; -3; 4; 5]
val y : maybe_negative = Found_negative -3
val exists : 'a t -> f:('a -> bool) -> bool

Returns true if and only if there exists an element for which the provided function evaluates to true. This is a short-circuiting operation.

val for_all : 'a t -> f:('a -> bool) -> bool

Returns true if and only if the provided function evaluates to true for all elements. This is a short-circuiting operation.

val count : 'a t -> f:('a -> bool) -> int

Returns the number of elements for which the provided function evaluates to true.

val sum : (module Base__Container_intf.Summable with type t = 'sum) -> 'a t -> f:('a -> 'sum) -> 'sum

Returns the sum of f i for all i in the container.

val find : 'a t -> f:('a -> bool) -> 'a option

Returns as an option the first element for which f evaluates to true.

val find_map : 'a t -> f:('a -> 'b option) -> 'b option

Returns the first evaluation of f that returns Some, and returns None if there is no such element.

val to_list : 'a t -> 'a list
val to_array : 'a t -> 'a array
val min_elt : 'a t -> compare:('a -> 'a -> int) -> 'a option

Returns a minimum (resp maximum) element from the collection using the provided compare function, or None if the collection is empty. In case of a tie, the first element encountered while traversing the collection is returned. The implementation uses fold so it has the same complexity as fold.

val max_elt : 'a t -> compare:('a -> 'a -> int) -> 'a option
include Base.Invariant.S1 with type 'a t := 'a t
val invariant : ('a -> unit) -> 'a t -> unit
val max_length : int

Maximum length of a normal array. The maximum length of a float array is max_length/2 on 32-bit machines and max_length on 64-bit machines.

val get : 'a t -> int -> 'a

Array.get a n returns the element number n of array a. The first element has number 0. The last element has number Array.length a - 1. You can also write a.(n) instead of Array.get a n.

Raise Invalid_argument "index out of bounds" if n is outside the range 0 to (Array.length a - 1).

val set : 'a t -> int -> 'a -> unit

Array.set a n x modifies array a in place, replacing element number n with x. You can also write a.(n) <- x instead of Array.set a n x.

Raise Invalid_argument "index out of bounds" if n is outside the range 0 to Array.length a - 1.

val unsafe_get : 'a t -> int -> 'a

Unsafe version of get. Can cause arbitrary behavior when used for an out-of-bounds array access.

val unsafe_set : 'a t -> int -> 'a -> unit

Unsafe version of set. Can cause arbitrary behavior when used for an out-of-bounds array access.

val create : len:int -> 'a -> 'a t

create ~len x creates an array of length len with the value x populated in each element.

val init : int -> f:(int -> 'a) -> 'a t

init n ~f creates an array of length n where the ith element (starting at zero) is initialized with f i.

val make_matrix : dimx:int -> dimy:int -> 'a -> 'a t t

Array.make_matrix dimx dimy e returns a two-dimensional array (an array of arrays) with first dimension dimx and second dimension dimy. All the elements of this new matrix are initially physically equal to e. The element (x,y) of a matrix m is accessed with the notation m.(x).(y).

Raise Invalid_argument if dimx or dimy is negative or greater than Array.max_length.

If the value of e is a floating-point number, then the maximum size is only Array.max_length / 2.

val append : 'a t -> 'a t -> 'a t

Array.append v1 v2 returns a fresh array containing the concatenation of the arrays v1 and v2.

val concat : 'a t list -> 'a t

Like Array.append, but concatenates a list of arrays.

val copy : 'a t -> 'a t

Array.copy a returns a copy of a, that is, a fresh array containing the same elements as a.

val fill : 'a t -> pos:int -> len:int -> 'a -> unit

Array.fill a ofs len x modifies the array a in place, storing x in elements number ofs to ofs + len - 1.

Raise Invalid_argument "Array.fill" if ofs and len do not designate a valid subarray of a.

Array.blit v1 o1 v2 o2 len copies len elements from array v1, starting at element number o1, to array v2, starting at element number o2. It works correctly even if v1 and v2 are the same array, and the source and destination chunks overlap.

Raise Invalid_argument "Array.blit" if o1 and len do not designate a valid subarray of v1, or if o2 and len do not designate a valid subarray of v2.

int_blit and float_blit provide fast bound-checked blits for immediate data types. The unsafe versions do not bound-check the arguments.

include Base.Blit.S1 with type 'a t := 'a t
val blit : src:'a t -> src_pos:int -> dst:'a t -> dst_pos:int -> len:int -> unit
val blito : src:'a t -> ?src_pos:int -> ?src_len:int -> dst:'a t -> ?dst_pos:int -> unit -> unit
val unsafe_blit : src:'a t -> src_pos:int -> dst:'a t -> dst_pos:int -> len:int -> unit
val sub : 'a t -> pos:int -> len:int -> 'a t
val subo : ?pos:int -> ?len:int -> 'a t -> 'a t
val of_list : 'a list -> 'a t

Array.of_list l returns a fresh array containing the elements of l.

val map : 'a t -> f:('a -> 'b) -> 'b t

Array.map t ~f applies function f to all the elements of t, and builds an array with the results returned by f: [| f t.(0); f t.(1); ...; f t.(Array.length t - 1) |].

val folding_map : 'a t -> init:'b -> f:('b -> 'a -> 'b * 'c) -> 'c t

folding_map is a version of map that threads an accumulator through calls to f.

val folding_mapi : 'a t -> init:'b -> f:(int -> 'b -> 'a -> 'b * 'c) -> 'c t
val fold_map : 'a t -> init:'b -> f:('b -> 'a -> 'b * 'c) -> 'b * 'c t

Array.fold_map is a combination of Array.fold and Array.map that threads an accumulator through calls to f.

val fold_mapi : 'a t -> init:'b -> f:(int -> 'b -> 'a -> 'b * 'c) -> 'b * 'c t
val iteri : 'a t -> f:(int -> 'a -> unit) -> unit

Like Array.iter, but the function is applied to the index of the element as first argument, and the element itself as second argument.

val mapi : 'a t -> f:(int -> 'a -> 'b) -> 'b t

Like Array.map, but the function is applied to the index of the element as first argument, and the element itself as second argument.

val foldi : 'a t -> init:'b -> f:(int -> 'b -> 'a -> 'b) -> 'b
val fold_right : 'a t -> f:('a -> 'b -> 'b) -> init:'b -> 'b

Array.fold_right f a ~init computes f a.(0) (f a.(1) ( ... (f a.(n-1) init) ...)), where n is the length of the array a.

All sort functions in this module sort in increasing order by default.

val sort : ?pos:int -> ?len:int -> 'a t -> compare:('a -> 'a -> int) -> unit

sort uses constant heap space. stable_sort uses linear heap space.

To sort only part of the array, specify pos to be the index to start sorting from and len indicating how many elements to sort.

val stable_sort : 'a t -> compare:('a -> 'a -> int) -> unit
val is_sorted : 'a t -> compare:('a -> 'a -> int) -> bool
val is_sorted_strictly : 'a t -> compare:('a -> 'a -> int) -> bool

is_sorted_strictly xs ~compare iff is_sorted xs ~compare and no two consecutive elements in xs are equal according to compare.

val concat_map : 'a t -> f:('a -> 'b array) -> 'b array

Like List.concat_map, List.concat_mapi.

val concat_mapi : 'a t -> f:(int -> 'a -> 'b array) -> 'b array
val partition_tf : 'a t -> f:('a -> bool) -> 'a t * 'a t
val partitioni_tf : 'a t -> f:(int -> 'a -> bool) -> 'a t * 'a t
val cartesian_product : 'a t -> 'b t -> ('a * 'b) t
val transpose : 'a t t -> 'a t t option

transpose in the sense of a matrix transpose. It returns None if the arrays are not all the same length.

val transpose_exn : 'a t t -> 'a t t
val filter_opt : 'a option t -> 'a t

filter_opt array returns a new array where None entries are omitted and Some x entries are replaced with x. Note that this changes the index at which elements will appear.

val filter_map : 'a t -> f:('a -> 'b option) -> 'b t

filter_map ~f array maps f over array and filters None out of the results.

val filter_mapi : 'a t -> f:(int -> 'a -> 'b option) -> 'b t

Like filter_map but uses Array.mapi.

val for_alli : 'a t -> f:(int -> 'a -> bool) -> bool

Like for_all, but passes the index as an argument.

val existsi : 'a t -> f:(int -> 'a -> bool) -> bool

Like exists, but passes the index as an argument.

val counti : 'a t -> f:(int -> 'a -> bool) -> int

Like count, but passes the index as an argument.

Functions with the 2 suffix raise an exception if the lengths of the two given arrays aren't the same.

val iter2_exn : 'a t -> 'b t -> f:('a -> 'b -> unit) -> unit
val map2_exn : 'a t -> 'b t -> f:('a -> 'b -> 'c) -> 'c t
val fold2_exn : 'a t -> 'b t -> init:'c -> f:('c -> 'a -> 'b -> 'c) -> 'c
val for_all2_exn : 'a t -> 'b t -> f:('a -> 'b -> bool) -> bool

for_all2_exn t1 t2 ~f fails if length t1 <> length t2.

val exists2_exn : 'a t -> 'b t -> f:('a -> 'b -> bool) -> bool

exists2_exn t1 t2 ~f fails if length t1 <> length t2.

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

filter t ~f removes the elements for which f returns false.

val filteri : 'a t -> f:(int -> 'a -> bool) -> 'a t

Like filter except f also receives the index.

val swap : 'a t -> int -> int -> unit

swap arr i j swaps the value at index i with that at index j.

val rev_inplace : 'a t -> unit

rev_inplace t reverses t in place.

val of_list_rev : 'a list -> 'a t

of_list_rev l converts from list then reverses in place.

val of_list_map : 'a list -> f:('a -> 'b) -> 'b t

of_list_map l ~f is the same as of_list (List.map l ~f).

val of_list_mapi : 'a list -> f:(int -> 'a -> 'b) -> 'b t

of_list_mapi l ~f is the same as of_list (List.mapi l ~f).

val of_list_rev_map : 'a list -> f:('a -> 'b) -> 'b t

of_list_rev_map l ~f is the same as of_list (List.rev_map l ~f).

val of_list_rev_mapi : 'a list -> f:(int -> 'a -> 'b) -> 'b t

of_list_rev_mapi l ~f is the same as of_list (List.rev_mapi l ~f).

val map_inplace : 'a t -> f:('a -> 'a) -> unit

Modifies an array in place, applying f to every element of the array

val find_exn : 'a t -> f:('a -> bool) -> 'a

find_exn f t returns the first a in t for which f t.(i) is true. It raises Caml.Not_found or Not_found_s if there is no such a.

val find_map_exn : 'a t -> f:('a -> 'b option) -> 'b

Returns the first evaluation of f that returns Some. Raises Caml.Not_found or Not_found_s if f always returns None.

val findi : 'a t -> f:(int -> 'a -> bool) -> (int * 'a) option

findi t f returns the first index i of t for which f i t.(i) is true

val findi_exn : 'a t -> f:(int -> 'a -> bool) -> int * 'a

findi_exn t f returns the first index i of t for which f i t.(i) is true. It raises Caml.Not_found or Not_found_s if there is no such element.

val find_mapi : 'a t -> f:(int -> 'a -> 'b option) -> 'b option

find_mapi t f is like find_map but passes the index as an argument.

val find_mapi_exn : 'a t -> f:(int -> 'a -> 'b option) -> 'b

find_mapi_exn is like find_map_exn but passes the index as an argument.

val find_consecutive_duplicate : 'a t -> equal:('a -> 'a -> bool) -> ('a * 'a) option

find_consecutive_duplicate t ~equal returns the first pair of consecutive elements (a1, a2) in t such that equal a1 a2. They are returned in the same order as they appear in t.

val reduce : 'a t -> f:('a -> 'a -> 'a) -> 'a option

reduce f [a1; ...; an] is Some (f (... (f (f a1 a2) a3) ...) an). Returns None on the empty array.

val reduce_exn : 'a t -> f:('a -> 'a -> 'a) -> 'a
val permute : ?random_state:Base.Random.State.t -> 'a t -> unit

permute ?random_state t randomly permutes t in place.

permute side-effects random_state by repeated calls to Random.State.int. If random_state is not supplied, permute uses Random.State.default.

val random_element : ?random_state:Base.Random.State.t -> 'a t -> 'a option

random_element ?random_state t is None if t is empty, else it is Some x for some x chosen uniformly at random from t.

random_element side-effects random_state by calling Random.State.int. If random_state is not supplied, random_element uses Random.State.default.

val random_element_exn : ?random_state:Base.Random.State.t -> 'a t -> 'a
val zip : 'a t -> 'b t -> ('a * 'b) t option

zip is like List.zip, but for arrays.

val zip_exn : 'a t -> 'b t -> ('a * 'b) t
val unzip : ('a * 'b) t -> 'a t * 'b t

unzip is like List.unzip, but for arrays.

val sorted_copy : 'a t -> compare:('a -> 'a -> int) -> 'a t

sorted_copy ar compare returns a shallow copy of ar that is sorted. Similar to List.sort

val last : 'a t -> 'a
val equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> bool
val to_sequence : 'a t -> 'a Base.Sequence.t

The input array is copied internally so that future modifications of it do not change the sequence.

val to_sequence_mutable : 'a t -> 'a Base.Sequence.t

The input array is shared with the sequence and modifications of it will result in modification of the sequence.

Extensions

We add extensions for Int and Float arrays to make them bin-able, comparable, sexpable, and blit-able (via Blit.S). Permissioned provides fine-grained access control for arrays.

Operations supporting "normalized" indexes are also available.

module Int : sig ... end
module Float : sig ... end
val normalize : 'a t -> Base.Int.t -> Base.Int.t

normalize array index returns a new index into the array such that if the index is less than zero, the returned index will "wrap around" -- i.e., array.(normalize array (-1)) returns the last element of the array.

val slice : 'a t -> Base.Int.t -> Base.Int.t -> 'a t

slice t start stop returns a new array including elements t.(start) through t.(stop-1), normalized Python-style with the exception that stop = 0 is treated as stop = length t.

val nget : 'a t -> Base.Int.t -> 'a

Array access with normalized index.

val nset : 'a t -> Base.Int.t -> 'a -> Base.Unit.t

Array modification with normalized index.

module Permissioned : sig ... end

The Permissioned module gives the ability to restrict permissions on an array, so you can give a function read-only access to an array, create an immutable array, etc.