Array (3)
NAME
Array - Array operations.Module
Module ArrayDocumentation
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.
Since
4.03.0
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.
Since
4.03.0
===
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)
.
Since
4.03.0
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)
.
Since
4.03.0
val mem
:
'a -> 'a array -> bool
mem a l
is true if and only if
a
is equal
to an element of
l
.
Since
4.03.0
val memq
:
'a -> 'a array -> bool
Same as
Array.mem
, but uses physical equality instead of structural
equality to compare array elements.
Since
4.03.0
===
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, 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
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.