Module ArrayLabels

module ArrayLabels: sig .. end

Array operations.

The labeled version of this module can be used as described in the StdLabels module.

type t('a) = array('a);

An alias for the type of arrays.

let length: array('a) => int;

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

let get: (array('a), 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).

let set: (array('a), 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.

let make: (int, 'a) => array('a);

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.

let create: (int, 'a) => array('a);

Deprecated.create is an alias for ArrayLabels.make.

let create_float: int => array(float);

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

Since 4.03

let make_float: int => array(float);

Deprecated.make_float is an alias for ArrayLabels.create_float.

let init: (int, ~f: int => 'a) => array('a);

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.

let make_matrix: (~dimx: int, ~dimy: int, 'a) => array(array('a));

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.

let create_matrix: (~dimx: int, ~dimy: int, 'a) => array(array('a));

Deprecated.create_matrix is an alias for ArrayLabels.make_matrix.

let append: (array('a), array('a)) => array('a);

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

Raises Invalid_argument if length v1 + length v2 > Sys.max_array_length.

let concat: list(array('a)) => array('a);

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

let sub: (array('a), ~pos: int, ~len: int) => array('a);

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.

let copy: array('a) => array('a);

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

let fill: (array('a), ~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.

let blit:
  (
    ~src: array('a),
    ~src_pos: int,
    ~dst: array('a),
    ~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.

let to_list: array('a) => list('a);

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

let of_list: list('a) => array('a);

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

Raises Invalid_argument if the length of l is greater than Sys.max_array_length.

Iterators

let iter: (~f: 'a => unit, array('a)) => 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); ().

let iteri: (~f: (int, 'a) => unit, array('a)) => 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.

let map: (~f: 'a => 'b, array('a)) => array('b);

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) |].

let mapi: (~f: (int, 'a) => 'b, array('a)) => array('b);

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.

let fold_left: (~f: ('a, 'b) => 'a, ~init: 'a, array('b)) => '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.

let fold_right: (~f: ('b, 'a) => 'a, array('b), ~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

let iter2: (~f: ('a, 'b) => unit, array('a), array('b)) => unit;

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

Since 4.05.0
Raises Invalid_argument if the arrays are not the same size.

let map2: (~f: ('a, 'b) => 'c, array('a), array('b)) => array('c);

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)|].

Since 4.05.0
Raises Invalid_argument if the arrays are not the same size.

Array scanning

let for_all: (~f: 'a => bool, array('a)) => 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

let exists: (~f: 'a => bool, array('a)) => 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

let for_all2: (~f: ('a, 'b) => bool, array('a), array('b)) => bool;

Same as ArrayLabels.for_all, but for a two-argument predicate.

Since 4.11.0
Raises Invalid_argument if the two arrays have different lengths.

let exists2: (~f: ('a, 'b) => bool, array('a), array('b)) => bool;

Same as ArrayLabels.exists, but for a two-argument predicate.

Since 4.11.0
Raises Invalid_argument if the two arrays have different lengths.

let mem: ('a, ~set: array('a)) => bool;

mem a ~set is true if and only if a is structurally equal to an element of l (i.e. there is an x in l such that compare a x = 0).

Since 4.03.0

let memq: ('a, ~set: array('a)) => bool;

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

Since 4.03.0

Sorting

let sort: (~cmp: ('a, 'a) => int, array('a)) => 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, compare is a suitable comparison function. 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

let stable_sort: (~cmp: ('a, 'a) => int, array('a)) => 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 a temporary array of length n/2, where n is the length of the array. It is usually faster than the current implementation of ArrayLabels.sort.

let fast_sort: (~cmp: ('a, 'a) => int, array('a)) => unit;

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

Iterators

let to_seq: array('a) => Seq.t('a);

Iterate on the array, in increasing order. Modifications of the array during iteration will be reflected in the iterator.

Since 4.07

let to_seqi: array('a) => Seq.t((int, 'a));

Iterate on the array, in increasing order, yielding indices along elements. Modifications of the array during iteration will be reflected in the iterator.

Since 4.07

let of_seq: Seq.t('a) => array('a);

Create an array from the generator

Since 4.07