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Module BatteriesExceptionless.ArraySource

include module type of BatArray with module Labels := BatArray.Labels and module Cap := BatArray.Cap
Sourcetype 'a t = 'a array

The type of arrays.

include BatEnum.Enumerable with type 'a enumerable = 'a t
Sourcetype 'a enumerable = 'a t

The data structure, e.g. 'a List.t

include BatInterfaces.Mappable with type 'a mappable = 'a t
Sourcetype 'a mappable = 'a t

The data structure, e.g. 'a List.t

Sourceval length : 'a array -> int

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

Sourceval 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.

Sourceval 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.

Sourceval 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.

  • 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.

Sourceval create_float : int -> float array
Sourceval make_float : int -> float array

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

  • since 2.3.0
Sourceval init_matrix : int -> int -> (int -> int -> 'a) -> 'a array array
Sourceval of_seq : 'a Seq.t -> 'a array
Sourceval to_seq : 'a array -> 'a Seq.t
Sourceval to_seqi : 'a array -> (int * 'a) Seq.t
Sourceval 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.

  • 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.

Sourceval 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).

  • 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.

Sourceval append : 'a array -> 'a array -> 'a array

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

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

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

Sourceval 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.

  • raises Invalid_argument

    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.

Sourceval copy : 'a array -> 'a array

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

Sourceval 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.

Sourceval 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.

  • raises Invalid_argument

    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.

Sourceval to_list : 'a array -> 'a list

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

Sourceval split : ('a * 'b) array -> 'a array * 'b array

Array.split a converts the array of pairs a into a pair of arrays.

Sourceval combine : 'a array -> 'b array -> ('a * 'b) array

combine [|a1; ...; an|] [|b1; ...; bn|] is [|(a1,b1); ...; (an,bn)|]. Raise Invalid_argument if the two arrays have different lengths.

  • since 3.4.0
Sourceval of_list : 'a list -> 'a array

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

Sourceval max : 'a array -> 'a

max a returns the largest value in a as judged by Pervasives.compare

Sourceval min : 'a array -> 'a

min a returns the smallest value in a as judged by Pervasives.compare

Sourceval min_max : 'a array -> 'a * 'a

min_max a returns the (smallest, largest) pair of values from a as judged by Pervasives.compare

Sourceval sum : int array -> int

sum l returns the sum of the integers of l

Sourceval fsum : float array -> float

fsum l returns the sum of the floats of l

Sourceval kahan_sum : float array -> float

kahan_sum l returns a numerically-accurate sum of the floats of l.

You should consider using Kahan summation when you really care about very small differences in the result, while the result or one of the intermediate sums can be very large (which usually results in loss of precision of floating-point addition).

The worst-case rounding error is constant, instead of growing with (the square root of) the length of the input array as with fsum. On the other hand, processing each element requires four floating-point operations instead of one. See the wikipedia article on Kahan summation for more details.

  • since 2.2.0
Sourceval avg : int array -> float

avg l returns the average of l

  • since 2.1
Sourceval favg : float array -> float

favg l returns the average of l

  • since 2.1
Sourceval left : 'a array -> int -> 'a array

left r len returns the array containing the len first elements of r. If r contains less than len elements, it returns r.

Examples: Array.left [|0;1;2;3;4;5;6|] 4 = [|0;1;2;3|] Array.left [|1;2;3|] 0 = [||] Array.left [|1;2;3|] 10 = [|1;2;3|]

Sourceval right : 'a array -> int -> 'a array

left r len returns the array containing the len last characters of r. If r contains less than len characters, it returns r.

Example: Array.right [|1;2;3;4;5;6|] 4 = [|3;4;5;6|]

Sourceval head : 'a array -> int -> 'a array

as left

Sourceval tail : 'a array -> int -> 'a array

tail r pos returns the array containing all but the pos first characters of r

Example: Array.tail [|1;2;3;4;5;6|] 4 = [|5;6|]

Sourceval 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); ().

Sourceval 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) |].

Sourceval iteri : (int -> 'a -> unit) -> 'a array -> unit

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

Sourceval 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.

Sourceval 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.

Sourceval fold_left_map : ('a -> 'b -> 'a * 'c) -> 'a -> 'b array -> 'a * 'c array

fold_left_map is a combination of fold_left and map that threads an accumulator through calls to f.

  • since 3.4.0
Sourceval fold_while : ('acc -> 'a -> bool) -> ('acc -> 'a -> 'acc) -> 'acc -> 'a array -> 'acc * int

fold_while p f init a, accumulates elements x of array a using function f, as long as the predicate p acc x holds. At the end, the accumulated value along with the first index i where p acc a.(i) does not hold is returned. If the returned index is equal to length a, the whole array was folded.

Sourceval fold : ('a -> 'b -> 'a) -> 'a -> 'b array -> 'a

Alias for fold_left.

Sourceval 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.

Sourceval modify : ('a -> 'a) -> 'a array -> unit

modify f a replaces every element x of a with f x.

Sourceval modifyi : (int -> 'a -> 'a) -> 'a array -> unit

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

Sourceval fold_lefti : ('a -> int -> 'b -> 'a) -> 'a -> 'b array -> 'a

As fold_left, but with the index of the element as additional argument

Sourceval fold_righti : (int -> 'b -> 'a -> 'a) -> 'b array -> 'a -> 'a

As fold_right, but with the index of the element as additional argument

Sourceval reduce : ('a -> 'a -> 'a) -> 'a array -> 'a

Array.reduce f a is fold_left f a.(0) [|a.(1); ..; a.(n-1)|]. This is useful for merging a group of things that have no reasonable default value to return if the group is empty.

Sourceval singleton : 'a -> 'a array

Create an array consisting of exactly one element.

  • since 2.1

Sorting

Sourceval 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, Pervasives.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 :

  • 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 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 :

  • cmp a.(i) a.(j) >= 0 if and only if i >= j
Sourceval 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.

Sourceval fast_sort : ('a -> 'a -> int) -> 'a array -> unit

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

Sourceval decorate_stable_sort : ('a -> 'b) -> 'a array -> 'a array

decorate_stable_sort f a returns a sorted copy of a such that if f x < f y then x is earlier in the result than y. This function is useful when f is expensive, as it only computes f x once for each element in the array. See Schwartzian Transform.

It is unnecessary to have an additional comparison function as argument, as the builtin Pervasives.compare is used to compare the 'b values. This is deemed sufficient.

Sourceval decorate_fast_sort : ('a -> 'b) -> 'a array -> 'a array

As Array.decorate_stable_sort, but uses fast_sort internally.

Sourceval bsearch : 'a BatOrd.ord -> 'a array -> 'a -> [ `All_lower | `All_bigger | `Just_after of int | `Empty | `At of int ]

bsearch cmp arr x finds the index of the object x in the array arr, provided arr 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 (dichotomic search).

  • returns
    • `At i if cmp arr.(i) x = 0 (for some i)
    • `All_lower if all elements of arr are lower than x
    • `All_bigger if all elements of arr are bigger than x
    • `Just_after i if arr.(i) < x < arr.(i+1)
    • `Empty if the array is empty
  • since 2.2.0
Sourceval pivot_split : 'a BatOrd.ord -> 'a array -> 'a -> int * int

pivot_split cmp arr x assumes that arr is sorted w.r.t cmp. It splits an array arr of length len into three parts, by returning a couple (i,j) such as:

  • all elements with indices 0..i-1 (sub arr 0 i) are lower than x
  • all elements with indices i..j-1 (sub arr i (j-i)) are equal to x
  • all elements with indices j..len-1 (sub arr j (len-j)) are bigger than x

In particular, it returns:

  • (0, 0) if all elements of arr are bigger than x
  • (len, len) if all elements are lower than x
  • (0, len) if all elements are equal to x

Complexity: logarithmic in the size of the array

Operations on two arrays

Sourceval iter2 : ('a -> 'b -> unit) -> 'a array -> 'b array -> unit

Array.iter2 f [|a0; a1; ...; an|] [|b0; b1; ...; bn|] performs calls f a0 b0; f a1 b1; ...; f an bn in that order.

Sourceval iter2i : (int -> 'a -> 'b -> unit) -> 'a array -> 'b array -> unit

Array.iter2i f [|a0; a1; ...; an|] [|b0; b1; ...; bn|] performs calls f 0 a0 b0; f 1 a1 b1; ...; f n an bn in that order.

Sourceval for_all2 : ('a -> 'b -> bool) -> 'a array -> 'b array -> bool

As Array.for_all but on two arrays.

Sourceval exists2 : ('a -> 'b -> bool) -> 'a array -> 'b array -> bool

As Array.exists but on two arrays.

Sourceval map2 : ('a -> 'b -> 'c) -> 'a array -> 'b array -> 'c array

As Array.map but on two arrays.

Sourceval cartesian_product : 'a array -> 'b array -> ('a * 'b) array

Cartesian product of the two arrays.

  • since 2.2.0

Predicates

Sourceval for_all : ('a -> bool) -> 'a array -> bool

for_all p [|a0; a1; ...; an|] checks if all elements of the array satisfy the predicate p. That is, it returns (p a0) && (p a1) && ... && (p an).

Sourceval exists : ('a -> bool) -> 'a array -> bool

exists p [|a0; a1; ...; an|] checks if at least one element of the array satisfies the predicate p. That is, it returns (p a0) || (p a1) || ... || (p an).

Sourceval find_opt : ('a -> bool) -> 'a array -> 'a option

find_opt p a returns the first element of the array a that satisfies the predicate p, or None if there is no such element.

  • since 3.4.0
Sourceval mem : 'a -> 'a array -> bool

mem m a is true if and only if m is equal to an element of a.

Sourceval memq : 'a -> 'a array -> bool

Same as Array.mem but uses physical equality instead of structural equality to compare array elements.

Sourceval filter : ('a -> bool) -> 'a array -> 'a array

filter p a returns all the elements of the array a that satisfy the predicate p. The order of the elements in the input array is preserved.

Sourceval filteri : (int -> 'a -> bool) -> 'a array -> 'a array

As filter but with the index passed to the predicate.

Sourceval filter_map : ('a -> 'b option) -> 'a array -> 'b array

filter_map f e returns an array consisting of all elements x such that f y returns Some x , where y is an element of e.

Sourceval count_matching : ('a -> bool) -> 'a array -> int

count_matching p a returns the number of elements of a satisfying predicate p.

Sourceval find_all : ('a -> bool) -> 'a array -> 'a array

find_all is another name for Array.filter.

Sourceval partition : ('a -> bool) -> 'a array -> 'a array * 'a array

partition p a returns a pair of arrays (a1, a2), where a1 is the array of all the elements of a that satisfy the predicate p, and a2 is the array of all the elements of a that do not satisfy p. The order of the elements in the input array is preserved.

Array transformations

Sourceval rev : 'a array -> 'a array

Array reversal.

Sourceval rev_in_place : 'a array -> unit

In-place array reversal. The array argument is updated.

Conversions

Sourceval enum : 'a array -> 'a BatEnum.t

Returns an enumeration of the elements of an array. Behavior of the enumeration is undefined if the contents of the array changes afterwards.

Sourceval of_enum : 'a BatEnum.t -> 'a array

Build an array from an enumeration.

Sourceval backwards : 'a array -> 'a BatEnum.t

Returns an enumeration of the elements of an array, from last to first.

Sourceval of_backwards : 'a BatEnum.t -> 'a array

Build an array from an enumeration, with the first element of the enumeration as the last element of the array and vice versa.

Utilities

Sourceval range : 'a array -> int BatEnum.t

range a returns an enumeration of all valid indexes into the given array. For example, range [|2;4;6;8|] = 0--3.

Sourceval insert : 'a array -> 'a -> int -> 'a array

insert xs x i returns a copy of xs except the value x is inserted in position i (and all later indices are shifted to the right).

Sourceval remove_at : int -> 'a array -> 'a array

remove_at i a returns the array a without the element at index i.

  • since 3.3.0

Boilerplate code

Sourceval print : ?first:string -> ?last:string -> ?sep:string -> ('a, 'b) BatIO.printer -> ('a t, 'b) BatIO.printer

Print the contents of an array, with ~first preceding the first item (default: "[|"), ~last following the last item (default: "|]") and ~sep separating items (default: "; "). A printing function must be provided to print the items in the array.

Example: IO.to_string (Array.print Int.print) |2;4;66| = "|2; 4; 66|"

Sourceval compare : 'a BatOrd.comp -> 'a array BatOrd.comp

compare c generates the lexicographical order on arrays induced by c. That is, given a comparison function for the elements of an array, this will return a comparison function for arrays of that type.

Sourceval ord : 'a BatOrd.ord -> 'a array BatOrd.ord

Hoist an element comparison function to compare arrays of those elements, with shorter arrays less than longer ones, and lexicographically for arrays of the same size. This is a different ordering than compare, but is often faster.

Sourceval shuffle : ?state:Random.State.t -> 'a array -> unit

shuffle ~state:rs a randomly shuffles in place the elements of a. The optional random state rs allows to control the random numbers being used during shuffling (for reproducibility).

Shuffling is implemented using the Fisher-Yates algorithm and works in O(n), where n is the number of elements of a.

  • since 2.6.0
Sourceval equal : 'a BatOrd.eq -> 'a array BatOrd.eq

Hoist a equality test for elements to arrays. Arrays are only equal if their lengths are the same and corresponding elements test equal.

Override modules

The following modules replace functions defined in Array with functions behaving slightly differently but having the same name. This is by design: the functions are meant to override the corresponding functions of Array.

Sourcemodule Exceptionless : sig ... end

Operations on Array without exceptions.

Sourcemodule Incubator : sig ... end
include module type of struct include BatArray.Exceptionless end
Sourceval find : ('a -> bool) -> 'a BatArray.t -> 'a option

find p a returns Some x, where x is the first element of array a that satisfies the predicate p, or None if there is no such element.

Sourceval findi : ('a -> bool) -> 'a BatArray.t -> int option

findi p a returns Some n, where n is the index of the first element of array a that satisfies the predicate p, or None if there is no such element.

Sourcemodule Labels : sig ... end
Sourcemodule Cap : sig ... end
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