package containers

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package containers
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Array utils (Labeled version of CCArray)

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 = Random.State.t -> 'a
type 'a printer = Format.formatter -> 'a -> unit

Arrays

val length : 'a array -> int

Return the length (number of elements) of the given array.

val get : 'a array -> int -> 'a

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

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

val set : 'a array -> int -> 'a -> unit

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

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

val make : int -> 'a -> 'a array

ArrayLabels.make n x returns a fresh array of length n, initialized with x. All the elements of this new array are initially physically equal to x (in the sense of the == predicate). Consequently, if x is mutable, it is shared among all elements of the array, and modifying x through one of the array entries will modify all other entries at the same time.

Raise Invalid_argument if n < 0 or n > Sys.max_array_length. If the value of x is a floating-point number, then the maximum size is only Sys.max_array_length / 2.

val create : int -> 'a -> 'a array
val init : int -> f:(int -> 'a) -> 'a array

ArrayLabels.init n f returns a fresh array of length n, with element number i initialized to the result of f i. In other terms, ArrayLabels.init n f tabulates the results of f applied to the integers 0 to n-1.

Raise Invalid_argument if n < 0 or n > Sys.max_array_length. If the return type of f is float, then the maximum size is only Sys.max_array_length / 2.

val make_matrix : dimx:int -> dimy:int -> 'a -> 'a array array

ArrayLabels.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 Sys.max_array_length. If the value of e is a floating-point number, then the maximum size is only Sys.max_array_length / 2.

val create_matrix : dimx:int -> dimy:int -> 'a -> 'a array array
val append : 'a array -> 'a array -> 'a array

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

val concat : 'a array list -> 'a array

Same as ArrayLabels.append, but concatenates a list of arrays.

val sub : 'a array -> pos:int -> len:int -> 'a array

ArrayLabels.sub a start len returns a fresh array of length len, containing the elements number start to start + len - 1 of array a.

Raise Invalid_argument "Array.sub" if start and len do not designate a valid subarray of a; that is, if start < 0, or len < 0, or start + len > ArrayLabels.length a.

val copy : 'a array -> 'a array

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

val fill : 'a array -> pos:int -> len:int -> 'a -> unit

ArrayLabels.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.

val blit : src:'a array -> src_pos:int -> dst:'a array -> dst_pos:int -> len:int -> unit

ArrayLabels.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.

val to_list : 'a array -> 'a list

ArrayLabels.to_list a returns the list of all the elements of a.

val of_list : 'a list -> 'a array

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

val iter : f:('a -> unit) -> 'a array -> unit

ArrayLabels.iter f a applies function f in turn to all the elements of a. It is equivalent to f a.(0); f a.(1); ...; f a.(ArrayLabels.length a - 1); ().

val map : f:('a -> 'b) -> 'a array -> 'b array

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

val iteri : f:(int -> 'a -> unit) -> 'a array -> unit

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

val mapi : f:(int -> 'a -> 'b) -> 'a array -> 'b array

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

val fold_left : f:('a -> 'b -> 'a) -> init:'a -> 'b array -> 'a

ArrayLabels.fold_left f x a computes f (... (f (f x a.(0)) a.(1)) ...) a.(n-1), where n is the length of the array a.

val fold_right : f:('b -> 'a -> 'a) -> 'b array -> init:'a -> 'a

ArrayLabels.fold_right f a x computes f a.(0) (f a.(1) ( ... (f a.(n-1) x) ...)), where n is the length of the array a.

val exists : f:('a -> bool) -> 'a array -> bool

ArrayLabels.exists p [|a1; ...; an|] checks if at least one element of the array satisfies the predicate p. That is, it returns (p a1) || (p a2) || ... || (p an).

val for_all : f:('a -> bool) -> 'a array -> bool

ArrayLabels.for_all p [|a1; ...; an|] checks if all elements of the array satisfy the predicate p. That is, it returns (p a1) && (p a2) && ... && (p an).

val memq : 'a -> set:'a array -> bool

Same as ArrayLabels.mem, but uses physical equality instead of structural equality to compare list elements.

val create_float : int -> float array

ArrayLabels.create_float n returns a fresh float array of length n, with uninitialized data.

  • since 4.03
val make_float : int -> float array
Sorting
val sort : cmp:('a -> 'a -> int) -> 'a array -> unit

Sort an array in increasing order according to a comparison function. The comparison function must return 0 if its arguments compare as equal, a positive integer if the first is greater, and a negative integer if the first is smaller (see below for a complete specification). For example, Pervasives.compare is a suitable comparison function, provided there are no floating-point NaN values in the data. After calling ArrayLabels.sort, the array is sorted in place in increasing order. ArrayLabels.sort is guaranteed to run in constant heap space and (at most) logarithmic stack space.

The current implementation uses Heap Sort. It runs in constant stack space.

Specification of the comparison function: Let a be the array and cmp the comparison function. The following must be true for all x, y, z in a :

  • cmp x y > 0 if and only if cmp y x < 0
  • if cmp x y >= 0 and cmp y z >= 0 then cmp x z >= 0

When ArrayLabels.sort returns, a contains the same elements as before, reordered in such a way that for all i and j valid indices of a :

  • cmp a.(i) a.(j) >= 0 if and only if i >= j
val stable_sort : cmp:('a -> 'a -> int) -> 'a array -> unit

Same as ArrayLabels.sort, but the sorting algorithm is stable (i.e. elements that compare equal are kept in their original order) and not guaranteed to run in constant heap space.

The current implementation uses Merge Sort. It uses n/2 words of heap space, where n is the length of the array. It is usually faster than the current implementation of ArrayLabels.sort.

val fast_sort : cmp:('a -> 'a -> int) -> 'a array -> unit

Same as ArrayLabels.sort or ArrayLabels.stable_sort, whichever is faster on typical input.

module Floatarray = CCArray.Floatarray
type 'a t = 'a array
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 : f:('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 : f:(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 : f:('a -> 'b -> 'a) -> init:'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 ArrayLabels.fold_left

val foldi : f:('a -> int -> 'b -> 'a) -> init:'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 : f:('a -> 'b -> 'a * [ `Stop | `Continue ]) -> init:'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 : f:('acc -> 'a -> 'acc * 'b) -> init:'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 : f:('acc -> 'a -> 'acc) -> init:'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 : f:('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 : f:('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 : f:('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 : f:('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 : f:(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 : f:('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 : cmp:('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 : cmp:('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 : cmp:('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 : cmp:('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 : cmp:('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 : cmp:('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 : cmp:('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 : cmp:('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 -> key:'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 -> key:'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) -> key:'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 : f:('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 : f:('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 : f:('acc -> 'a -> 'b -> 'acc) -> init:'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 iter2 : f:('a -> 'b -> unit) -> 'a t -> 'b t -> unit

iter2 ~f a b iterates on the two arrays a and b stepwise. It is equivalent to f a0 b0; …; f a.(length a - 1) b.(length b - 1); ().

  • 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 : 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 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 map2 : f:('a -> 'b -> 'c) -> 'a t -> 'b t -> 'c t

map2 ~f a b applies function f to all elements of a and b, and builds an array with the results returned by f: [| f a.(0) b.(0); …; f a.(length a - 1) b.(length b - 1)|].

  • raises Invalid_argument

    if a and b have distinct lengths.

  • since 0.20
val rev : 'a t -> 'a t

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

  • since 0.20
val filter : f:('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 : f:('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 : f:('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 : f:('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
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