CCArray
Array utils
type 'a random_gen = Stdlib.Random.State.t -> 'a
type 'a printer = Stdlib.Format.formatter -> 'a -> unit
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
.
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
.
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.
create_float n
returns a fresh float array of length n
, with uninitialized data.
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
.
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)
.
append v1 v2
returns a fresh array containing the concatenation of the arrays v1
and v2
.
Same as append
, but concatenates a list of arrays.
sub a pos len
returns a fresh array of length len
, containing the elements number pos
to pos + len - 1
of array a
.
copy a
returns a copy of a
, that is, a fresh array containing the same elements as a
.
fill a pos len x
modifies the array a
in place, storing x
in elements number pos
to pos + len - 1
.
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.
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); ()
.
Same as iter
, but the function is applied to the index of the element as first argument, and the element itself as second argument.
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) |]
.
Same as map
, but the function is applied to the index of the element as first argument, and the element itself as second argument.
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
.
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
.
iter2 f a b
applies function f
to all the elements of a
and b
.
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)|]
.
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)
.
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)
.
Same as mem
, but uses physical equality instead of structural equality to compare list elements.
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
.
split [|(a1,b1); ...; (an,bn)|]
is ([|a1; ...; an|], [|b1; ...; bn|])
.
combine [|a1; ...; an|] [|b1; ...; bn|]
is [|(a1,b1); ...; (an,bn)|]
. Raise Invalid_argument
if the two arrays have different lengths.
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. 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
< 0cmp x y
>= 0 and cmp y z
>= 0 then cmp x z
>= 0When 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 >= jSame 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 a temporary array of length n/2
, where n
is the length of the array. It is usually faster than the current implementation of sort
.
Same as sort
or stable_sort
, whichever is faster on typical input.
val to_seqi : 'a array -> (int * 'a) Stdlib.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.
val of_seq : 'a Stdlib.Seq.t -> 'a array
Create an array from the generator
val empty : 'a t
empty
is the empty array, physically equal to [||]
.
equal eq a1 a2
is true
if the lengths of a1
and a2
are the same and if their corresponding elements test equal, using eq
.
compare cmp a1 a2
compares arrays a1
and a2
using the function comparison cmp
.
val swap : 'a t -> int -> int -> unit
swap a i j
swaps elements at indices i
and j
.
val get_safe : 'a t -> int -> 'a option
get_safe a i
returns Some a.(i)
if i
is a valid index.
val map_inplace : ('a -> 'a) -> 'a t -> unit
map_inplace f a
replace all elements of a
by its image by f
.
val mapi_inplace : (int -> 'a -> 'a) -> 'a t -> unit
mapi_inplace f a
replace all elements of a
by its image by f
.
val fold : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'a
fold f init a
computes f (… (f (f init a.(0)) a.(1)) …) a.(n-1)
, where n
is the length of the array a
. Same as Array.fold_left
val foldi : ('a -> int -> 'b -> 'a) -> 'a -> 'b t -> 'a
foldi f init a
is just like fold
, but it also passes in the index of each element as the second argument to the folded function f
.
val fold_while : ('a -> 'b -> 'a * [ `Stop | `Continue ]) -> 'a -> 'b t -> 'a
fold_while f init a
folds left on array a
until a stop condition via ('a, `Stop)
is indicated by the accumulator.
fold_map f init a
is a fold_left
-like function, but it also maps the array to another array.
scan_left f init a
returns the array [|init; f init x0; f (f init a.(0)) a.(1); …|]
.
val reverse_in_place : 'a t -> unit
reverse_in_place a
reverses the array a
in place.
val sorted : ('a -> 'a -> int) -> 'a t -> 'a array
sorted f a
makes a copy of a
and sorts it with f
.
val sort_indices : ('a -> 'a -> int) -> 'a t -> int array
sort_indices f a
returns a new array b
, with the same length as a
, such that b.(i)
is the index at which the i
-th element of sorted f a
appears in a
. a
is not modified.
In other words, map (fun i -> a.(i)) (sort_indices f a) = sorted f a
. sort_indices
yields the inverse permutation of sort_ranking
.
val sort_ranking : ('a -> 'a -> int) -> 'a t -> int array
sort_ranking f a
returns a new array b
, with the same length as a
, such that b.(i)
is the index at which the i
-th element of a
appears in sorted f a
. a
is not modified.
In other words, map (fun i -> (sorted f a).(i)) (sort_ranking f a) = a
. sort_ranking
yields the inverse permutation of sort_indices
.
In the absence of duplicate elements in a
, we also have lookup_exn a.(i) (sorted a) = (sorted_ranking a).(i)
.
val mem : ?eq:('a -> 'a -> bool) -> 'a -> 'a t -> bool
mem ~eq x a
return true if x is present in a
. Linear time.
val find_map : ('a -> 'b option) -> 'a t -> 'b option
find_map f a
returns Some y
if there is an element x
such that f x = Some y
. Otherwise returns None
.
val find_map_i : (int -> 'a -> 'b option) -> 'a t -> 'b option
find_map_i f a
is like find_map
, but the index of the element is also passed to the predicate function f
.
val find_idx : ('a -> bool) -> 'a t -> (int * 'a) option
find_idx f a
returns Some (i,x)
where x
is the i
-th element of a
, and f x
holds. Otherwise returns None
.
val max : ('a -> 'a -> int) -> 'a t -> 'a option
max cmp a
returns None
if a
is empty, otherwise, returns Some e
where e
is a maximum element in a
with respect to cmp
.
val argmax : ('a -> 'a -> int) -> 'a t -> int option
argmax cmp a
returns None
if a
is empty, otherwise, returns Some i
where i
is the index of a maximum element in a
with respect to cmp
.
val min : ('a -> 'a -> int) -> 'a t -> 'a option
min cmp a
returns None
if a
is empty, otherwise, returns Some e
where e
is a minimum element in a
with respect to cmp
.
val argmin : ('a -> 'a -> int) -> 'a t -> int option
argmin cmp a
returns None
if a
is empty, otherwise, returns Some i
where i
is the index of a minimum element in a
with respect to cmp
.
lookup ~cmp key a
lookups the index of some key key
in a sorted array a
. Undefined behavior if the array a
is not sorted wrt ~cmp
. Complexity: O(log (n))
(dichotomic search).
val bsearch :
cmp:('a -> 'a -> int) ->
'a ->
'a t ->
[ `All_lower | `All_bigger | `Just_after of int | `Empty | `At of int ]
bsearch ~cmp key a
finds the index of the object key
in the array a
, provided a
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 a
(dichotomic search).
for_all2 f [|a1; …; an|] [|b1; …; bn|]
is true
if each pair of elements ai bi
satisfies the predicate f
. That is, it returns (f a1 b1) && (f a2 b2) && … && (f an bn)
.
exists2 f [|a1; …; an|] [|b1; …; bn|]
is true
if any pair of elements ai bi
satisfies the predicate f
. That is, it returns (f a1 b1) || (f a2 b2) || … || (f an bn)
.
fold2 f init a b
fold on two arrays a
and b
stepwise. It computes f (… (f init a1 b1) …) an bn
.
val shuffle : 'a t -> unit
shuffle a
randomly shuffles the array a
, in place.
val shuffle_with : Stdlib.Random.State.t -> 'a t -> unit
shuffle_with rs a
randomly shuffles the array a
(like shuffle
) but a specialized random state rs
is used to control the random numbers being produced during shuffling (for reproducibility).
val random_choose : 'a t -> 'a random_gen
random_choose a rs
randomly chooses an element of a
.
to_string ~sep item_to_string a
print a
to a string using sep
as a separator between elements of a
.
to_iter a
returns an iter
of the elements of an array a
. The input array a
is shared with the sequence and modification of it will result in modification of the iterator.
val to_seq : 'a t -> 'a Stdlib.Seq.t
to_seq a
returns a Seq.t
of the elements of an array a
. The input array a
is shared with the sequence and modification of it will result in modification of the sequence. Renamed from to_std_seq
since 3.0.
val pp :
?pp_start:unit printer ->
?pp_stop:unit printer ->
?pp_sep:unit printer ->
'a printer ->
'a t printer
pp ~pp_start ~pp_stop ~pp_sep pp_item ppf a
formats the array a
on ppf
. Each element is formatted with pp_item
, pp_start
is called at the beginning, pp_stop
is called at the end, pp_sep
is called between each elements. By defaults pp_start
and pp_stop
does nothing and pp_sep
defaults to (fun out -> Format.fprintf out ",@ ").
val pp_i :
?pp_start:unit printer ->
?pp_stop:unit printer ->
?pp_sep:unit printer ->
(int -> 'a printer) ->
'a t printer
pp_i ~pp_start ~pp_stop ~pp_sep pp_item ppf a
prints the array a
on ppf
. The printing function pp_item
is giving both index and element. pp_start
is called at the beginning, pp_stop
is called at the end, pp_sep
is called between each elements. By defaults pp_start
and pp_stop
does nothing and pp_sep
defaults to (fun out -> Format.fprintf out ",@ ").
filter f a
filters elements out of the array a
. Only the elements satisfying the given predicate f
will be kept.
filter_map f [|a1; …; an|]
calls (f a1) … (f an)
and returns an array b
consisting of all elements bi
such as f ai = Some bi
. When f
returns None
, the corresponding element of a
is discarded.
monoid_product f a b
passes all combinaisons of tuples from the two arrays a
and b
to the function f
.
flat_map f a
transforms each element of a
into an array, then flattens.
val except_idx : 'a t -> int -> 'a list
except_idx a i
removes the element of a
at given index i
, and returns the list of the other elements.
val random : 'a random_gen -> 'a t random_gen
val random_non_empty : 'a random_gen -> 'a t random_gen
val random_len : int -> 'a random_gen -> 'a t random_gen
module type MONO_ARRAY = sig ... end
val sort_generic :
(module MONO_ARRAY with type elt = 'elt and type t = 'arr) ->
cmp:('elt -> 'elt -> int) ->
'arr ->
unit
sort_generic (module M) ~cmp a
sorts the array a
, without allocating (eats stack space though). Performance might be lower than Array.sort
.
It is convenient to open CCArray.Infix
to access the infix operators without cluttering the scope too much.
module Infix : sig ... end