Module CCArray

Array utils

type 'a iter = ('a -> unit) -> unit

Fast internal iterator.

  • since 2.8
type 'a gen = unit -> 'a option
type 'a equal = 'a -> 'a -> bool
type 'a ord = 'a -> 'a -> int
type 'a random_gen = Stdlib.Random.State.t -> 'a
type 'a printer = Stdlib.Format.formatter -> 'a -> unit

Arrays

type !'a t = 'a array
val length : 'a array -> int
val get : 'a array -> int -> 'a
val set : 'a array -> int -> 'a -> unit
val make : int -> 'a -> 'a array
val create_float : int -> float array
val init : int -> (int -> 'a) -> 'a array
val make_matrix : int -> int -> 'a -> 'a array array
val append : 'a array -> 'a array -> 'a array
val concat : 'a array list -> 'a array
val sub : 'a array -> int -> int -> 'a array
val copy : 'a array -> 'a array
val fill : 'a array -> int -> int -> 'a -> unit
val blit : 'a array -> int -> 'a array -> int -> int -> unit
val to_list : 'a array -> 'a list
val of_list : 'a list -> 'a array
val iter : ('a -> unit) -> 'a array -> unit
val iteri : (int -> 'a -> unit) -> 'a array -> unit
val map : ('a -> 'b) -> 'a array -> 'b array
val mapi : (int -> 'a -> 'b) -> 'a array -> 'b array
val fold_left : ('acc -> 'a -> 'acc) -> 'acc -> 'a array -> 'acc
val fold_left_map : ('acc -> 'a -> 'acc * 'b) -> 'acc -> 'a array -> 'acc * 'b array
val fold_right : ('a -> 'acc -> 'acc) -> 'a array -> 'acc -> 'acc
val iter2 : ('a -> 'b -> unit) -> 'a array -> 'b array -> unit
val map2 : ('a -> 'b -> 'c) -> 'a array -> 'b array -> 'c array
val for_all : ('a -> bool) -> 'a array -> bool
val exists : ('a -> bool) -> 'a array -> bool
val memq : 'a -> 'a array -> bool
val find_opt : ('a -> bool) -> 'a array -> 'a option
val find_index : ('a -> bool) -> 'a array -> int option
val find_mapi : (int -> 'a -> 'b option) -> 'a array -> 'b option
val split : ('a * 'b) array -> 'a array * 'b array
val combine : 'a array -> 'b array -> ('a * 'b) array
val sort : ('a -> 'a -> int) -> 'a array -> unit
val stable_sort : ('a -> 'a -> int) -> 'a array -> unit
val fast_sort : ('a -> 'a -> int) -> 'a array -> unit
val to_seqi : 'a array -> (int * 'a) Stdlib.Seq.t
val of_seq : 'a Stdlib.Seq.t -> 'a array
val unsafe_get : 'a array -> int -> 'a
val unsafe_set : 'a array -> int -> 'a -> unit
module Floatarray : sig ... end
val empty : 'a t

empty is the empty array, physically equal to [||].

val equal : 'a equal -> 'a t equal

equal eq a1 a2 is true if the lengths of a1 and a2 are the same and if their corresponding elements test equal, using eq.

val compare : 'a ord -> 'a t ord

compare cmp a1 a2 compares arrays a1 and a2 using the function comparison cmp.

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

swap a i j swaps elements at indices i and j.

  • since 1.4
val get_safe : 'a t -> int -> 'a option

get_safe a i returns Some a.(i) if i is a valid index.

  • since 0.18
val map_inplace : ('a -> 'a) -> 'a t -> unit

map_inplace f a replace all elements of a by its image by f.

  • since 3.8
val mapi_inplace : (int -> 'a -> 'a) -> 'a t -> unit

mapi_inplace f a replace all elements of a by its image by f.

  • since 3.10
val fold : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'a

fold f init a computes f (… (f (f init a.(0)) a.(1)) …) a.(n-1), where n is the length of the array a. Same as Array.fold_left

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

foldi f init a is just like fold, but it also passes in the index of each element as the second argument to the folded function f.

val fold_while : ('a -> 'b -> 'a * [ `Stop | `Continue ]) -> 'a -> 'b t -> 'a

fold_while f init a folds left on array a until a stop condition via ('a, `Stop) is indicated by the accumulator.

  • since 0.8
val fold_map : ('acc -> 'a -> 'acc * 'b) -> 'acc -> 'a t -> 'acc * 'b t

fold_map f init a is a fold_left-like function, but it also maps the array to another array.

  • since 1.2, but only
  • since 2.1 with labels
val scan_left : ('acc -> 'a -> 'acc) -> 'acc -> 'a t -> 'acc t

scan_left f init a returns the array [|init; f init x0; f (f init a.(0)) a.(1); …|] .

  • since 1.2, but only
  • since 2.1 with labels
val reverse_in_place : 'a t -> unit

reverse_in_place a reverses the array a in place.

val sorted : ('a -> 'a -> int) -> 'a t -> 'a array

sorted f a makes a copy of a and sorts it with f.

  • since 1.0
val sort_indices : ('a -> 'a -> int) -> 'a t -> int array

sort_indices f a returns a new array b, with the same length as a, such that b.(i) is the index at which the i-th element of sorted f a appears in a. a is not modified.

In other words, map (fun i -> a.(i)) (sort_indices f a) = sorted f a. sort_indices yields the inverse permutation of sort_ranking.

  • since 1.0
val sort_ranking : ('a -> 'a -> int) -> 'a t -> int array

sort_ranking f a returns a new array b, with the same length as a, such that b.(i) is the index at which the i-th element of a appears in sorted f a. a is not modified.

In other words, map (fun i -> (sorted f a).(i)) (sort_ranking f a) = a. sort_ranking yields the inverse permutation of sort_indices.

In the absence of duplicate elements in a, we also have lookup_exn a.(i) (sorted a) = (sorted_ranking a).(i).

  • since 1.0
val mem : ?eq:('a -> 'a -> bool) -> 'a -> 'a t -> bool

mem ~eq x a return true if x is present in a. Linear time.

  • since 3.0
val find_map : ('a -> 'b option) -> 'a t -> 'b option

find_map f a returns Some y if there is an element x such that f x = Some y. Otherwise returns None.

  • since 1.3, but only
  • since 2.1 with labels
val find_map_i : (int -> 'a -> 'b option) -> 'a t -> 'b option

find_map_i f a is like find_map, but the index of the element is also passed to the predicate function f.

  • since 1.3, but only
  • since 2.1 with labels
val find_idx : ('a -> bool) -> 'a t -> (int * 'a) option

find_idx f a returns Some (i,x) where x is the i-th element of a, and f x holds. Otherwise returns None.

  • since 0.3.4
val max : ('a -> 'a -> int) -> 'a t -> 'a option

max cmp a returns None if a is empty, otherwise, returns Some e where e is a maximum element in a with respect to cmp.

  • since 3.12
val max_exn : ('a -> 'a -> int) -> 'a t -> 'a

max_exn cmp a is like max, but

  • raises Invalid_argument

    if a is empty.

  • since 3.12
val argmax : ('a -> 'a -> int) -> 'a t -> int option

argmax cmp a returns None if a is empty, otherwise, returns Some i where i is the index of a maximum element in a with respect to cmp.

  • since 3.12
val argmax_exn : ('a -> 'a -> int) -> 'a t -> int

argmax_exn cmp a is like argmax, but

  • raises Invalid_argument

    if a is empty.

  • since 3.12
val min : ('a -> 'a -> int) -> 'a t -> 'a option

min cmp a returns None if a is empty, otherwise, returns Some e where e is a minimum element in a with respect to cmp.

  • since 3.12
val min_exn : ('a -> 'a -> int) -> 'a t -> 'a

min_exn cmp a is like min, but

  • raises Invalid_argument

    if a is empty.

  • since 3.12
val argmin : ('a -> 'a -> int) -> 'a t -> int option

argmin cmp a returns None if a is empty, otherwise, returns Some i where i is the index of a minimum element in a with respect to cmp.

  • since 3.12
val argmin_exn : ('a -> 'a -> int) -> 'a t -> int

argmin_exn cmp a is like argmin, but

  • raises Invalid_argument

    if a is empty.

  • since 3.12
val lookup : cmp:'a ord -> 'a -> 'a t -> int option

lookup ~cmp key a lookups the index of some key key in a sorted array a. Undefined behavior if the array a is not sorted wrt ~cmp. Complexity: O(log (n)) (dichotomic search).

  • returns

    None if the key key is not present, or Some i (i the index of the key) otherwise.

val lookup_exn : cmp:'a ord -> 'a -> 'a t -> int

lookup_exn ~cmp key a is like lookup, but

  • raises Not_found

    if the key key is not present.

val bsearch : cmp:('a -> 'a -> int) -> 'a -> 'a t -> [ `All_lower | `All_bigger | `Just_after of int | `Empty | `At of int ]

bsearch ~cmp key a finds the index of the object key in the array a, provided a is sorted using cmp. If the array is not sorted, the result is not specified (may raise Invalid_argument).

Complexity: O(log n) where n is the length of the array a (dichotomic search).

  • returns
    • `At i if cmp a.(i) key = 0 (for some i).
    • `All_lower if all elements of a are lower than key.
    • `All_bigger if all elements of a are bigger than key.
    • `Just_after i if a.(i) < key < a.(i+1).
    • `Empty if the array a is empty.
  • raises Invalid_argument

    if the array is found to be unsorted w.r.t cmp.

  • since 0.13
val for_all2 : ('a -> 'b -> bool) -> 'a t -> 'b t -> bool

for_all2 f [|a1; …; an|] [|b1; …; bn|] is true if each pair of elements ai bi satisfies the predicate f. That is, it returns (f a1 b1) && (f a2 b2) && … && (f an bn).

  • raises Invalid_argument

    if arrays have distinct lengths. Allow different types.

  • since 0.20
val exists2 : ('a -> 'b -> bool) -> 'a t -> 'b t -> bool

exists2 f [|a1; …; an|] [|b1; …; bn|] is true if any pair of elements ai bi satisfies the predicate f. That is, it returns (f a1 b1) || (f a2 b2) || … || (f an bn).

  • raises Invalid_argument

    if arrays have distinct lengths. Allow different types.

  • since 0.20
val fold2 : ('acc -> 'a -> 'b -> 'acc) -> 'acc -> 'a t -> 'b t -> 'acc

fold2 f init a b fold on two arrays a and b stepwise. It computes f (… (f init a1 b1) …) an bn.

  • raises Invalid_argument

    if a and b have distinct lengths.

  • since 0.20
val shuffle : 'a t -> unit

shuffle a randomly shuffles the array a, in place.

val shuffle_with : Stdlib.Random.State.t -> 'a t -> unit

shuffle_with rs a randomly shuffles the array a (like shuffle) but a specialized random state rs is used to control the random numbers being produced during shuffling (for reproducibility).

val random_choose : 'a t -> 'a random_gen

random_choose a rs randomly chooses an element of a.

  • raises Not_found

    if the array/slice is empty.

val to_string : ?sep:string -> ('a -> string) -> 'a array -> string

to_string ~sep item_to_string a print a to a string using sep as a separator between elements of a.

  • since 2.7
val to_iter : 'a t -> 'a iter

to_iter a returns an iter of the elements of an array a. The input array a is shared with the sequence and modification of it will result in modification of the iterator.

  • since 2.8
val to_seq : 'a t -> 'a Stdlib.Seq.t

to_seq a returns a Seq.t of the elements of an array a. The input array a is shared with the sequence and modification of it will result in modification of the sequence. Renamed from to_std_seq since 3.0.

  • since 3.0
val to_gen : 'a t -> 'a gen

to_gen a returns a gen of the elements of an array a.

IO

val pp : ?pp_start:unit printer -> ?pp_stop:unit printer -> ?pp_sep:unit printer -> 'a printer -> 'a t printer

pp ~pp_start ~pp_stop ~pp_sep pp_item ppf a formats the array a on ppf. Each element is formatted with pp_item, pp_start is called at the beginning, pp_stop is called at the end, pp_sep is called between each elements. By defaults pp_start and pp_stop does nothing and pp_sep defaults to (fun out -> Format.fprintf out ",@ ").

val pp_i : ?pp_start:unit printer -> ?pp_stop:unit printer -> ?pp_sep:unit printer -> (int -> 'a printer) -> 'a t printer

pp_i ~pp_start ~pp_stop ~pp_sep pp_item ppf a prints the array a on ppf. The printing function pp_item is giving both index and element. pp_start is called at the beginning, pp_stop is called at the end, pp_sep is called between each elements. By defaults pp_start and pp_stop does nothing and pp_sep defaults to (fun out -> Format.fprintf out ",@ ").

val rev : 'a t -> 'a t

rev a copies the array a and reverses it in place.

  • since 0.20
val filter : ('a -> bool) -> 'a t -> 'a t

filter f a filters elements out of the array a. Only the elements satisfying the given predicate f will be kept.

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

filter_map f [|a1; …; an|] calls (f a1) … (f an) and returns an array b consisting of all elements bi such as f ai = Some bi. When f returns None, the corresponding element of a is discarded.

val monoid_product : ('a -> 'b -> 'c) -> 'a t -> 'b t -> 'c t

monoid_product f a b passes all combinaisons of tuples from the two arrays a and b to the function f.

  • since 2.8
val flat_map : ('a -> 'b t) -> 'a t -> 'b array

flat_map f a transforms each element of a into an array, then flattens.

val except_idx : 'a t -> int -> 'a list

except_idx a i removes the element of a at given index i, and returns the list of the other elements.

val random : 'a random_gen -> 'a t random_gen
val random_non_empty : 'a random_gen -> 'a t random_gen
val random_len : int -> 'a random_gen -> 'a t random_gen

Generic Functions

module type MONO_ARRAY = sig ... end
val sort_generic : (module MONO_ARRAY with type elt = 'elt and type t = 'arr) -> cmp:('elt -> 'elt -> int) -> 'arr -> unit

sort_generic (module M) ~cmp a sorts the array a, without allocating (eats stack space though). Performance might be lower than Array.sort.

  • since 0.14

Infix Operators

It is convenient to open CCArray.Infix to access the infix operators without cluttering the scope too much.

module Infix : sig ... end
include module type of Infix
val (>>=) : 'a t -> ('a -> 'b t) -> 'b t

a >>= f is the infix version of flat_map.

val (>>|) : 'a t -> ('a -> 'b) -> 'b t

a >>| f is the infix version of map.

  • since 0.8
val (>|=) : 'a t -> ('a -> 'b) -> 'b t

a >|= f is the infix version of map.

  • since 0.8
val (--) : int -> int -> int t

x -- y creates an array containing integers in the range x .. y. Bounds included.

val (--^) : int -> int -> int t

x --^ y creates an array containing integers in the range x .. y. Right bound excluded.

  • since 0.17
val let+ : 'a t -> ('a -> 'b) -> 'b t
val and+ : 'a t -> 'b t -> ('a * 'b) t
val let* : 'a t -> ('a -> 'b t) -> 'b t
val and* : 'a t -> 'b t -> ('a * 'b) t