List (p.dune-private-libs.2.9.3.doc.dune-private-libs.stdune.Stdune.List)

include module type of struct include ListLabels end

Sourceval length : 'a list -> int

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

Sourceval compare_lengths : 'a list -> 'b list -> int

Compare the lengths of two lists. compare_lengths l1 l2 is equivalent to compare (length l1) (length l2), except that the computation stops after reaching the end of the shortest list.

since 4.05.0

Sourceval compare_length_with : 'a list -> len:int -> int

Compare the length of a list to an integer. compare_length_with l len is equivalent to compare (length l) len, except that the computation stops after at most len iterations on the list.

since 4.05.0

Sourceval hd : 'a list -> 'a

Return the first element of the given list.

raises Failure
if the list is empty.

Sourceval tl : 'a list -> 'a list

Return the given list without its first element.

raises Failure
if the list is empty.

Sourceval nth_opt : 'a list -> int -> 'a option

Return the n-th element of the given list. The first element (head of the list) is at position 0. Return None if the list is too short.

raises Invalid_argument
if n is negative.

since 4.05

Sourceval rev : 'a list -> 'a list

List reversal.

Sourceval append : 'a list -> 'a list -> 'a list

Concatenate two lists. Same function as the infix operator @. Not tail-recursive (length of the first argument). The @ operator is not tail-recursive either.

Sourceval rev_append : 'a list -> 'a list -> 'a list

rev_append l1 l2 reverses l1 and concatenates it with l2. This is equivalent to (rev l1) @ l2, but rev_append is tail-recursive and more efficient.

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

Concatenate a list of lists. The elements of the argument are all concatenated together (in the same order) to give the result. Not tail-recursive (length of the argument + length of the longest sub-list).

Sourceval flatten : 'a list list -> 'a list

Same as concat. Not tail-recursive (length of the argument + length of the longest sub-list).

Comparison

Iterators

Sourceval iter : f:('a -> unit) -> 'a list -> unit

iter ~f [a1; ...; an] applies function f in turn to a1; ...; an. It is equivalent to begin f a1; f a2; ...; f an; () end.

Sourceval iteri : f:(int -> 'a -> unit) -> 'a list -> unit

Same as 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.

since 4.00.0

Sourceval map : f:('a -> 'b) -> '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.

Sourceval mapi : f:(int -> 'a -> 'b) -> 'a list -> 'b list

Same as 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.

since 4.00.0

Sourceval rev_map : f:('a -> 'b) -> 'a list -> 'b list

rev_map ~f l gives the same result as rev (map f l), but is tail-recursive and more efficient.

Source

val fold_left_map : 
  f:('a -> 'b -> 'a * 'c) ->
  init:'a ->
  'b list ->
  'a * 'c list

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

since 4.11.0

Sourceval fold_left : f:('a -> 'b -> 'a) -> init:'a -> 'b list -> 'a

fold_left ~f ~init [b1; ...; bn] is f (... (f (f init b1) b2) ...) bn.

Sourceval fold_right : f:('a -> 'b -> 'b) -> 'a list -> init:'b -> 'b

fold_right ~f [a1; ...; an] ~init is f a1 (f a2 (... (f an init) ...)). Not tail-recursive.

Iterators on two lists

Sourceval iter2 : f:('a -> 'b -> unit) -> 'a list -> 'b list -> unit

iter2 ~f [a1; ...; an] [b1; ...; bn] calls in turn f a1 b1; ...; f an bn.

raises Invalid_argument
if the two lists are determined to have different lengths.

Sourceval map2 : f:('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list

map2 ~f [a1; ...; an] [b1; ...; bn] is [f a1 b1; ...; f an bn].

raises Invalid_argument
if the two lists are determined to have different lengths. Not tail-recursive.

Sourceval rev_map2 : f:('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list

rev_map2 ~f l1 l2 gives the same result as rev (map2 f l1 l2), but is tail-recursive and more efficient.

Source

val fold_left2 : 
  f:('a -> 'b -> 'c -> 'a) ->
  init:'a ->
  'b list ->
  'c list ->
  'a

fold_left2 ~f ~init [a1; ...; an] [b1; ...; bn] is f (... (f (f init a1 b1) a2 b2) ...) an bn.

raises Invalid_argument
if the two lists are determined to have different lengths.

Source

val fold_right2 : 
  f:('a -> 'b -> 'c -> 'c) ->
  'a list ->
  'b list ->
  init:'c ->
  'c

fold_right2 ~f [a1; ...; an] [b1; ...; bn] ~init is f a1 b1 (f a2 b2 (... (f an bn init) ...)).

raises Invalid_argument
if the two lists are determined to have different lengths. Not tail-recursive.

List scanning

Sourceval for_all : f:('a -> bool) -> 'a list -> bool

for_all ~f [a1; ...; an] checks if all elements of the list satisfy the predicate f. That is, it returns (f a1) && (f a2) && ... && (f an) for a non-empty list and true if the list is empty.

Sourceval exists : f:('a -> bool) -> 'a list -> bool

exists ~f [a1; ...; an] checks if at least one element of the list satisfies the predicate f. That is, it returns (f a1) || (f a2) || ... || (f an) for a non-empty list and false if the list is empty.

Sourceval exists2 : f:('a -> 'b -> bool) -> 'a list -> 'b list -> bool

Same as exists, but for a two-argument predicate.

raises Invalid_argument
if the two lists are determined to have different lengths.

Sourceval mem : 'a -> set:'a list -> bool

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

Sourceval memq : 'a -> set:'a list -> bool

Same as mem, but uses physical equality instead of structural equality to compare list elements.

List searching

Sourceval find_opt : f:('a -> bool) -> 'a list -> 'a option

find ~f l returns the first element of the list l that satisfies the predicate f. Returns None if there is no value that satisfies f in the list l.

since 4.05

Sourceval filter : f:('a -> bool) -> 'a list -> 'a list

filter ~f l returns all the elements of the list l that satisfy the predicate f. The order of the elements in the input list is preserved.

Sourceval find_all : f:('a -> bool) -> 'a list -> 'a list

find_all is another name for filter.

Sourceval partition : f:('a -> bool) -> 'a list -> 'a list * 'a list

partition ~f l returns a pair of lists (l1, l2), where l1 is the list of all the elements of l that satisfy the predicate f, and l2 is the list of all the elements of l that do not satisfy f. The order of the elements in the input list is preserved.

Association lists

Sourceval assoc_opt : 'a -> ('a * 'b) list -> 'b option

assoc_opt a l returns the value associated with key a in the list of pairs l. That is, assoc_opt a [ ...; (a,b); ...] = Some b if (a,b) is the leftmost binding of a in list l. Returns None if there is no value associated with a in the list l.

since 4.05

Sourceval assq : 'a -> ('a * 'b) list -> 'b

Same as assoc, but uses physical equality instead of structural equality to compare keys.

Sourceval assq_opt : 'a -> ('a * 'b) list -> 'b option

Same as assoc_opt, but uses physical equality instead of structural equality to compare keys.

since 4.05.0

Sourceval mem_assoc : 'a -> map:('a * 'b) list -> bool

Same as assoc, but simply return true if a binding exists, and false if no bindings exist for the given key.

Sourceval mem_assq : 'a -> map:('a * 'b) list -> bool

Same as mem_assoc, but uses physical equality instead of structural equality to compare keys.

Sourceval remove_assoc : 'a -> ('a * 'b) list -> ('a * 'b) list

remove_assoc a l returns the list of pairs l without the first pair with key a, if any. Not tail-recursive.

Sourceval remove_assq : 'a -> ('a * 'b) list -> ('a * 'b) list

Same as remove_assoc, but uses physical equality instead of structural equality to compare keys. Not tail-recursive.

Lists of pairs

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

Transform a list of pairs into a pair of lists: split [(a1,b1); ...; (an,bn)] is ([a1; ...; an], [b1; ...; bn]). Not tail-recursive.

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

Transform a pair of lists into a list of pairs: combine [a1; ...; an] [b1; ...; bn] is [(a1,b1); ...; (an,bn)].

raises Invalid_argument
if the two lists have different lengths. Not tail-recursive.

Sorting

Sourceval fast_sort : cmp:('a -> 'a -> int) -> 'a list -> 'a list

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

Sourceval merge : cmp:('a -> 'a -> int) -> 'a list -> 'a list -> 'a list

Merge two lists: Assuming that l1 and l2 are sorted according to the comparison function cmp, merge ~cmp l1 l2 will return a sorted list containing 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).

Lists and Sequences

Sourceval to_seq : 'a list -> 'a Seq.t

Iterate on the list.

since 4.07

Sourceval of_seq : 'a Seq.t -> 'a list

Create a list from a sequence.

since 4.07

Sourcetype 'a t = 'a list

Sourceval is_empty : _ t -> bool

Sourceval is_non_empty : _ t -> bool

Sourceval filter_map : 'a t -> f:('a -> 'b option) -> 'b t

Sourceval filter_opt : 'a option t -> 'a t

Sourceval filteri : 'a t -> f:(int -> 'a -> bool) -> 'a t

Sourceval concat_map : 'a t -> f:('a -> 'b t) -> 'b t

Sourceval partition_map : 'a t -> f:('a -> ('b, 'c) Either.t) -> 'b t * 'c t

Sourceval rev_map_append : 'a t -> 'b t -> f:('a -> 'b) -> 'b t

Sourceval rev_partition_map : 'a t -> f:('a -> ('b, 'c) Either.t) -> 'b t * 'c t

Sourcetype ('a, 'b) skip_or_either =

| Skip
| Left of 'a
| Right of 'b

Source

val filter_partition_map : 
  'a t ->
  f:('a -> ('b, 'c) skip_or_either) ->
  'b t * 'c t

Source

val rev_filter_partition_map : 
  'a t ->
  f:('a -> ('b, 'c) skip_or_either) ->
  'b t * 'c t

Sourceval find : 'a t -> f:('a -> bool) -> 'a option

Sourceval findi : 'a t -> f:('a -> bool) -> ('a * int) option

Sourceval find_exn : 'a t -> f:('a -> bool) -> 'a

Sourceval find_map : 'a t -> f:('a -> 'b option) -> 'b option

Sourceval last : 'a t -> 'a option

Sourceval destruct_last : 'a t -> ('a list * 'a) option

Sourceval sort : 'a t -> compare:('a -> 'a -> Ordering.t) -> 'a t

Sourceval stable_sort : 'a t -> compare:('a -> 'a -> Ordering.t) -> 'a t

Sourceval sort_uniq : 'a t -> compare:('a -> 'a -> Ordering.t) -> 'a t

Sourceval compare : 'a t -> 'a t -> compare:('a -> 'a -> Ordering.t) -> Ordering.t

Sourceval assoc : ('a * 'b) t -> 'a -> 'b option

Sourceval singleton : 'a -> 'a t

Sourceval nth : 'a t -> int -> 'a option

Sourceval physically_equal : 'a t -> 'a t -> bool

Sourceval init : int -> f:(int -> 'a) -> 'a list

Sourceval hd_opt : 'a t -> 'a option

Sourceval equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> bool

Sourceval hash : ('a -> int) -> 'a list -> int

Sourceval cons : 'a -> 'a t -> 'a t

Sourceval fold_map : 'a list -> init:'b -> f:('b -> 'a -> 'b * 'c) -> 'b * 'c list

Sourceval unzip : ('a * 'b) t -> 'a t * 'b t

Source

val for_all2 : 
  'a list ->
  'b list ->
  f:('a -> 'b -> bool) ->
  (bool, [ `Length_mismatch ]) result

Sourceval reduce : 'a list -> f:('a -> 'a -> 'a) -> 'a option

Sourceval min : 'a list -> f:('a -> 'a -> Ordering.t) -> 'a option

Sourceval max : 'a list -> f:('a -> 'a -> Ordering.t) -> 'a option