table of contents
| ArrayLabels(3) | OCaml library | ArrayLabels(3) |
NAME¶
ArrayLabels - Array operations.
Module¶
Module ArrayLabels
Documentation¶
Module ArrayLabels
: sig end
Array operations.
The labeled version of this module can be used as described in the StdLabels module.
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 ArrayLabels.make .
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 ArrayLabels.create_float .
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 ArrayLabels.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 .
Raises Invalid_argument if length v1 + length v2 > Sys.max_array_length .
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
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 .
Raises Invalid_argument if the length of l is greater than Sys.max_array_length .
Iterators¶
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 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 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 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
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_left_map : f:('a -> 'b -> 'a * 'c) -> init:'a -> 'b array -> 'a * 'c array
fold_left_map is a combination of ArrayLabels.fold_left and ArrayLabels.map that threads an accumulator through calls to f .
Since 4.13.0
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 .
Since 4.05.0
Raises Invalid_argument if the arrays are not the same size.
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)|] .
Since 4.05.0
Raises Invalid_argument if the arrays are not the same size.
Array scanning¶
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 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_all2 : f:('a -> 'b -> bool) -> 'a array -> 'b array -> 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.
val exists2 : f:('a -> 'b -> bool) -> 'a array -> 'b array -> 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.
val mem : 'a -> set:'a array -> 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
val memq : 'a -> set:'a array -> bool
Same as ArrayLabels.mem , but uses physical equality instead of structural equality to compare list elements.
Since 4.03.0
val find_opt : f:('a -> bool) -> 'a array -> 'a option
find_opt ~f a returns the first element of the array a that satisfies the predicate f , or None if there is no value that satisfies f in the array a .
Since 4.13.0
val find_map : f:('a -> 'b option) -> 'a array -> 'b option
find_map ~f a applies f to the elements of a in order, and returns the first result of the form Some v , or None if none exist.
Since 4.13.0
Arrays of pairs¶
val split : ('a * 'b) array -> 'a array * 'b array
split [|(a1,b1); ...; (an,bn)|] is ([|a1; ...; an|], [|b1; ...; bn|]) .
Since 4.13.0
val 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 4.13.0
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, 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
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 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 .
val fast_sort : cmp:('a -> 'a -> int) -> 'a array -> unit
Same as ArrayLabels.sort or ArrayLabels.stable_sort , whichever is faster on typical input.
Arrays and Sequences¶
val to_seq : 'a array -> 'a Seq.t
Iterate on the array, in increasing order. Modifications of the array during iteration will be reflected in the sequence.
Since 4.07
val to_seqi : 'a array -> (int * 'a) Seq.t
Iterate on the array, in increasing order, yielding indices along elements. Modifications of the array during iteration will be reflected in the sequence.
Since 4.07
val of_seq : 'a Seq.t -> 'a array
Create an array from the generator
Since 4.07
| 2024-03-14 | OCamldoc |