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Module Array

module Array: sig .. end
Array operations.
val length : 'a array -> int
Return the length (number of elements) of the given array.
val get : 'a array -> int -> 'a
Array.get a n returns the element number n of array a. The first element has number 0. The last element has number Array.length a - 1. You can also write a.(n) instead of Array.get a n.

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

val set : 'a array -> int -> 'a -> unit
Array.set a n x modifies array a in place, replacing element number n with x. You can also write a.(n) <- x instead of Array.set a n x.

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

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

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
Deprecated.Array.create is an alias for Array.make.
val create_float : int -> float array
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.Array.make_float is an alias for Array.create_float.
val init : int -> (int -> 'a) -> 'a array
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, Array.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 : int -> int -> 'a -> 'a array 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).

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 : int -> int -> 'a -> 'a array array
Deprecated.Array.create_matrix is an alias for Array.make_matrix.
val append : 'a array -> 'a array -> 'a array
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 Array.append, but concatenates a list of arrays.
val sub : 'a array -> int -> int -> 'a array
Array.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 > Array.length a.

val copy : 'a array -> 'a array
Array.copy a returns a copy of a, that is, a fresh array containing the same elements as a.
val fill : 'a array -> int -> int -> 'a -> unit
Array.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 : 'a array -> int -> 'a array -> int -> int -> unit
Array.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
Array.to_list a returns the list of all the elements of a.
val of_list : 'a list -> 'a array
Array.of_list l returns a fresh array containing the elements of l.

Iterators

val iter : ('a -> unit) -> 'a array -> unit
Array.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.(Array.length a - 1); ().
val iteri : (int -> 'a -> unit) -> 'a array -> unit
Same as Array.iter, but the function is applied with the index of the element as first argument, and the element itself as second argument.
val map : ('a -> 'b) -> 'a array -> 'b array
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.(Array.length a - 1) |].
val mapi : (int -> 'a -> 'b) -> 'a array -> 'b array
Same as Array.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 : ('a -> 'b -> 'a) -> 'a -> 'b array -> 'a
Array.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 : ('b -> 'a -> 'a) -> 'b array -> 'a -> 'a
Array.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.

Iterators on two arrays

val iter2 : ('a -> 'b -> unit) -> 'a array -> 'b array -> unit
Array.iter2 f a b applies function f to all the elements of a and b. Raise Invalid_argument if the arrays are not the same size.
val map2 : ('a -> 'b -> 'c) -> 'a array -> 'b array -> 'c array
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.(Array.length a - 1) b.(Array.length b - 1)|]. Raise Invalid_argument if the arrays are not the same size.

Array scanning

val for_all : ('a -> bool) -> 'a array -> bool
Array.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 exists : ('a -> bool) -> 'a array -> bool
Array.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 mem : 'a -> 'a array -> bool
mem a l is true if and only if a is equal to an element of l.
val memq : 'a -> 'a array -> bool
Same as Array.mem, but uses physical equality instead of structural equality to compare array elements.

Sorting

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

When Array.sort returns, a contains the same elements as before, reordered in such a way that for all i and j valid indices of a : 
val stable_sort : ('a -> 'a -> int) -> 'a array -> unit
Same as Array.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 Array.sort.

val fast_sort : ('a -> 'a -> int) -> 'a array -> unit
Same as Array.sort or Array.stable_sort, whichever is faster on typical input.