Module Stdlib.ArrayLabels

type 'a t = 'a array

An alias for the type of arrays.

val length : 'a array -> int

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

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

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

raises Invalid_argument

if n is outside the range 0 to (length a - 1).

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

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

raises Invalid_argument

if n is outside the range 0 to length a - 1.

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

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.

raises 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
deprecated

create is an alias for make.

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

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

raises 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

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).

raises 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
deprecated

create_matrix is an alias for make_matrix.

val append : 'a array -> 'a array -> 'a array

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 append, but concatenates a list of arrays.

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

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

raises Invalid_argument

if pos and len do not designate a valid subarray of a; that is, if pos < 0, or len < 0, or pos + len > length a.

val copy : 'a array -> 'a array

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

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

raises Invalid_argument

if pos 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

blit ~src ~src_pos ~dst ~dst_pos ~len copies len elements from array src, starting at element number src_pos, to array dst, starting at element number dst_pos. It works correctly even if src and dst are the same array, and the source and destination chunks overlap.

raises Invalid_argument

if src_pos and len do not designate a valid subarray of src, or if dst_pos and len do not designate a valid subarray of dst.

val to_list : 'a array -> 'a list

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

val of_list : 'a list -> 'a array

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

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

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.(length a - 1); ().

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

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.(length a - 1) |].

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

Same as 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 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

fold_left ~f ~init a computes f (... (f (f init 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

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.

Iterators on two arrays

val iter2 : f:('a -> 'b -> unit) -> 'a array -> 'b array -> unit

iter2 ~f a b applies function f to all the elements of a and b.

raises Invalid_argument

if the arrays are not the same size.

since
4.05.0
val map2 : f:('a -> 'b -> 'c) -> 'a array -> 'b array -> 'c array

map2 ~f a b applies function f to all the 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 the arrays are not the same size.

since
4.05.0

Array scanning

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

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

since
4.03.0
val for_all : f:('a -> bool) -> 'a array -> bool

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

since
4.03.0
val mem : 'a -> set:'a array -> bool

mem x ~set is true if and only if x is equal to an element of set.

since
4.03.0
val memq : 'a -> set:'a array -> bool

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

since
4.03.0
val create_float : int -> float array

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

since
4.03
val make_float : int -> float array
deprecated

make_float is an alias for create_float.

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, Stdlib.compare is a suitable comparison function, provided there are no floating-point NaN values in the data. After calling sort, the array is sorted in place in increasing order. 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 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 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 sort.

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

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

Iterators

val to_seq : 'a array -> 'a Stdlib.Seq.t

Iterate on the array, in increasing order

since
4.07
val to_seqi : 'a array -> (int * 'a) Stdlib.Seq.t

Iterate on the array, in increasing order, yielding indices along elements

since
4.07
val of_seq : 'a Stdlib.Seq.t -> 'a array

Create an array from the generator

since
4.07