module List: sig .. endSome functions are flagged as not tail-recursive. A tail-recursive function uses constant stack space, while a non-tail-recursive function uses stack space proportional to the length of its list argument, which can be a problem with very long lists. When the function takes several list arguments, an approximate formula giving stack usage (in some unspecified constant unit) is shown in parentheses.
The above considerations can usually be ignored if your lists are not
longer than about 10000 elements.
let length: list('a) => int;
let hd: list('a) => 'a;
Failure "hd" if the list is empty.let tl: list('a) => list('a);
Failure "tl" if the list is empty.let nth: (list('a), int) => 'a;
n-th element of the given list.
The first element (head of the list) is at position 0.
Raise Failure "nth" if the list is too short.
Raise Invalid_argument "List.nth" if n is negative.let rev: list('a) => list('a);
let append: (list('a), list('a)) => list('a);
@.
Not tail-recursive (length of the first argument). The @
operator is not tail-recursive either.let rev_append: (list('a), list('a)) => list('a);
List.rev_append l1 l2 reverses l1 and concatenates it to l2.
This is equivalent to List.rev l1 @ l2, but rev_append is
tail-recursive and more efficient.let concat: list(list('a)) => list('a);
let flatten: list(list('a)) => list('a);
concat. Not tail-recursive
(length of the argument + length of the longest sub-list).let iter: ('a => unit, list('a)) => unit;
List.iter f [a1; ...; an] applies function f in turn to
a1; ...; an. It is equivalent to
begin f a1; f a2; ...; f an; () end.let iteri: ((int, 'a) => unit, list('a)) => unit;
List.iter, but the function is applied to the index of
the element as first argument (counting from 0), and the element
itself as second argument.let map: ('a => 'b, list('a)) => list('b);
List.map f [a1; ...; an] applies function f to a1, ..., an,
and builds the list [f a1; ...; f an]
with the results returned by f. Not tail-recursive.let mapi: ((int, 'a) => 'b, list('a)) => list('b);
List.map, but the function is applied to the index of
the element as first argument (counting from 0), and the element
itself as second argument. Not tail-recursive.let rev_map: ('a => 'b, list('a)) => list('b);
List.rev_map f l gives the same result as
List.rev (List.map f l), but is tail-recursive and
more efficient.let fold_left: (('a, 'b) => 'a, 'a, list('b)) => 'a;
List.fold_left f a [b1; ...; bn] is
f (... (f (f a b1) b2) ...) bn.let fold_right: (('a, 'b) => 'b, list('a), 'b) => 'b;
List.fold_right f [a1; ...; an] b is
f a1 (f a2 (... (f an b) ...)). Not tail-recursive.let iter2: (('a, 'b) => unit, list('a), list('b)) => unit;
List.iter2 f [a1; ...; an] [b1; ...; bn] calls in turn
f a1 b1; ...; f an bn.
Raise Invalid_argument if the two lists have
different lengths.let map2: (('a, 'b) => 'c, list('a), list('b)) => list('c);
List.map2 f [a1; ...; an] [b1; ...; bn] is
[f a1 b1; ...; f an bn].
Raise Invalid_argument if the two lists have
different lengths. Not tail-recursive.let rev_map2: (('a, 'b) => 'c, list('a), list('b)) => list('c);
List.rev_map2 f l1 l2 gives the same result as
List.rev (List.map2 f l1 l2), but is tail-recursive and
more efficient.let fold_left2: (('a, 'b, 'c) => 'a, 'a, list('b), list('c)) => 'a;
List.fold_left2 f a [b1; ...; bn] [c1; ...; cn] is
f (... (f (f a b1 c1) b2 c2) ...) bn cn.
Raise Invalid_argument if the two lists have
different lengths.let fold_right2: (('a, 'b, 'c) => 'c, list('a), list('b), 'c) => 'c;
List.fold_right2 f [a1; ...; an] [b1; ...; bn] c is
f a1 b1 (f a2 b2 (... (f an bn c) ...)).
Raise Invalid_argument if the two lists have
different lengths. Not tail-recursive.let for_all: ('a => bool, list('a)) => bool;
for_all p [a1; ...; an] checks if all elements of the list
satisfy the predicate p. That is, it returns
(p a1) && (p a2) && ... && (p an).let exists: ('a => bool, list('a)) => bool;
exists p [a1; ...; an] checks if at least one element of
the list satisfies the predicate p. That is, it returns
(p a1) || (p a2) || ... || (p an).let for_all2: (('a, 'b) => bool, list('a), list('b)) => bool;
List.for_all, but for a two-argument predicate.
Raise Invalid_argument if the two lists have
different lengths.let exists2: (('a, 'b) => bool, list('a), list('b)) => bool;
List.exists, but for a two-argument predicate.
Raise Invalid_argument if the two lists have
different lengths.let mem: ('a, list('a)) => bool;
mem a l is true if and only if a is equal
to an element of l.let memq: ('a, list('a)) => bool;
List.mem, but uses physical equality instead of structural
equality to compare list elements.let find: ('a => bool, list('a)) => 'a;
find p l returns the first element of the list l
that satisfies the predicate p.
Raise Not_found if there is no value that satisfies p in the
list l.let filter: ('a => bool, list('a)) => list('a);
filter p l returns all the elements of the list l
that satisfy the predicate p. The order of the elements
in the input list is preserved.let find_all: ('a => bool, list('a)) => list('a);
let partition: ('a => bool, list('a)) => (list('a), list('a));
partition p l returns a pair of lists (l1, l2), where
l1 is the list of all the elements of l that
satisfy the predicate p, and l2 is the list of all the
elements of l that do not satisfy p.
The order of the elements in the input list is preserved.let assoc: ('a, list(('a, 'b))) => 'b;
assoc a l returns the value associated with key a in the list of
pairs l. That is,
assoc a [ ...; (a,b); ...] = b
if (a,b) is the leftmost binding of a in list l.
Raise Not_found if there is no value associated with a in the
list l.let assq: ('a, list(('a, 'b))) => 'b;
List.assoc, but uses physical equality instead of structural
equality to compare keys.let mem_assoc: ('a, list(('a, 'b))) => bool;
List.assoc, but simply return true if a binding exists,
and false if no bindings exist for the given key.let mem_assq: ('a, list(('a, 'b))) => bool;
List.mem_assoc, but uses physical equality instead of
structural equality to compare keys.let remove_assoc: ('a, list(('a, 'b))) => list(('a, 'b));
remove_assoc a l returns the list of
pairs l without the first pair with key a, if any.
Not tail-recursive.let remove_assq: ('a, list(('a, 'b))) => list(('a, 'b));
List.remove_assoc, but uses physical equality instead
of structural equality to compare keys. Not tail-recursive.let split: list(('a, 'b)) => (list('a), list('b));
split [(a1,b1); ...; (an,bn)] is ([a1; ...; an], [b1; ...; bn]).
Not tail-recursive.let combine: (list('a), list('b)) => list(('a, 'b));
combine [a1; ...; an] [b1; ...; bn] is
[(a1,b1); ...; (an,bn)].
Raise Invalid_argument if the two lists
have different lengths. Not tail-recursive.let sort: (('a, 'a) => int, list('a)) => list('a);
Pervasives.compare is a suitable comparison function.
The resulting list is sorted in increasing order.
List.sort is guaranteed to run in constant heap space
(in addition to the size of the result list) and logarithmic
stack space.
The current implementation uses Merge Sort. It runs in constant
heap space and logarithmic stack space.
let stable_sort: (('a, 'a) => int, list('a)) => list('a);
List.sort, but the sorting algorithm is guaranteed to
be stable (i.e. elements that compare equal are kept in their
original order) .
The current implementation uses Merge Sort. It runs in constant
heap space and logarithmic stack space.
let fast_sort: (('a, 'a) => int, list('a)) => list('a);
let sort_uniq: (('a, 'a) => int, list('a)) => list('a);
let merge: (('a, 'a) => int, list('a), list('a)) => list('a);
l1 and l2 are sorted according to the
comparison function cmp, merge cmp l1 l2 will return a
sorted list containting all the elements of l1 and l2.
If several elements compare equal, the elements of l1 will be
before the elements of l2.
Not tail-recursive (sum of the lengths of the arguments).