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

include module type of CCShimsArray_

Documentation for the standard Array module

include Stdlib.Array
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 : int -> 'a -> 'a array
val create_float : int -> float array
val make_float : int -> float array
val init : int -> (int -> 'a) -> 'a array
val make_matrix : int -> int -> 'a -> 'a array array
val create_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 : ('a -> 'b -> 'a) -> 'a -> 'b array -> 'a
val fold_right : ('b -> 'a -> 'a) -> 'b array -> 'a -> 'a
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 mem : 'a -> 'a array -> bool
val memq : 'a -> 'a array -> bool
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_seq : 'a array -> 'a Stdlib.Seq.t
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 = Stdlib__array.Floatarray
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 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 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.

since
2.7
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

Let operators on OCaml >= 4.08.0, nothing otherwise

since
2.8
include CCShimsMkLet_.S with type 'a t_let := 'a array
type 'a t_let
val let+ : 'a t_let -> ('a -> 'b) -> 'b t_let
val and+ : 'a t_let -> 'b t_let -> ('a * 'b) t_let
val let* : 'a t_let -> ('a -> 'b t_let) -> 'b t_let
val and* : 'a t_let -> 'b t_let -> ('a * 'b) t_let