Module CCListLabels

Complements to list

type 'a sequence = ('a ‑> unit) ‑> unit
type 'a gen = unit ‑> 'a option
type 'a klist = unit ‑> [ `Nil | `Cons of 'a * 'a klist ]
type 'a printer = Format.formatter ‑> 'a ‑> unit
type 'a random_gen = Random.State.t ‑> 'a
include module type of ListLabels
val length : 'a list ‑> int
val hd : 'a list ‑> 'a
val compare_lengths : 'a list ‑> 'b list ‑> int
val compare_length_with : 'a list ‑> len:int ‑> int
val cons : 'a ‑> 'a list ‑> 'a list
val tl : 'a list ‑> 'a list
val nth : 'a list ‑> int ‑> 'a
val nth_opt : 'a list ‑> int ‑> 'a option
val rev : 'a list ‑> 'a list
val init : len:int ‑> f:(int ‑> 'a) ‑> 'a list
val append : 'a list ‑> 'a list ‑> 'a list
val rev_append : 'a list ‑> 'a list ‑> 'a list
val concat : 'a list list ‑> 'a list
val flatten : 'a list list ‑> 'a list
val iter : f:('a ‑> unit) ‑> 'a list ‑> unit
val iteri : f:(int ‑> 'a ‑> unit) ‑> 'a list ‑> unit
val map : f:('a ‑> 'b) ‑> 'a list ‑> 'b list
val mapi : f:(int ‑> 'a ‑> 'b) ‑> 'a list ‑> 'b list
val rev_map : f:('a ‑> 'b) ‑> 'a list ‑> 'b list
val fold_left : f:('a ‑> 'b ‑> 'a) ‑> init:'a ‑> 'b list ‑> 'a
val fold_right : f:('a ‑> 'b ‑> 'b) ‑> 'a list ‑> init:'b ‑> 'b
val iter2 : f:('a ‑> 'b ‑> unit) ‑> 'a list ‑> 'b list ‑> unit
val map2 : f:('a ‑> 'b ‑> 'c) ‑> 'a list ‑> 'b list ‑> 'c list
val rev_map2 : f:('a ‑> 'b ‑> 'c) ‑> 'a list ‑> 'b list ‑> 'c list
val fold_left2 : f:('a ‑> 'b ‑> 'c ‑> 'a) ‑> init:'a ‑> 'b list ‑> 'c list ‑> 'a
val fold_right2 : f:('a ‑> 'b ‑> 'c ‑> 'c) ‑> 'a list ‑> 'b list ‑> init:'c ‑> 'c
val for_all : f:('a ‑> bool) ‑> 'a list ‑> bool
val exists : f:('a ‑> bool) ‑> 'a list ‑> bool
val for_all2 : f:('a ‑> 'b ‑> bool) ‑> 'a list ‑> 'b list ‑> bool
val exists2 : f:('a ‑> 'b ‑> bool) ‑> 'a list ‑> 'b list ‑> bool
val mem : 'a ‑> set:'a list ‑> bool
val memq : 'a ‑> set:'a list ‑> bool
val find : f:('a ‑> bool) ‑> 'a list ‑> 'a
val find_opt : f:('a ‑> bool) ‑> 'a list ‑> 'a option
val filter : f:('a ‑> bool) ‑> 'a list ‑> 'a list
val find_all : f:('a ‑> bool) ‑> 'a list ‑> 'a list
val partition : f:('a ‑> bool) ‑> 'a list ‑> 'a list * 'a list
val assoc : 'a ‑> ('a * 'b) list ‑> 'b
val assoc_opt : 'a ‑> ('a * 'b) list ‑> 'b option
val assq : 'a ‑> ('a * 'b) list ‑> 'b
val assq_opt : 'a ‑> ('a * 'b) list ‑> 'b option
val mem_assoc : 'a ‑> map:('a * 'b) list ‑> bool
val mem_assq : 'a ‑> map:('a * 'b) list ‑> bool
val remove_assoc : 'a ‑> ('a * 'b) list ‑> ('a * 'b) list
val remove_assq : 'a ‑> ('a * 'b) list ‑> ('a * 'b) list
val split : ('a * 'b) list ‑> 'a list * 'b list
val combine : 'a list ‑> 'b list ‑> ('a * 'b) list
val sort : cmp:('a ‑> 'a ‑> int) ‑> 'a list ‑> 'a list
val stable_sort : cmp:('a ‑> 'a ‑> int) ‑> 'a list ‑> 'a list
val fast_sort : cmp:('a ‑> 'a ‑> int) ‑> 'a list ‑> 'a list
val sort_uniq : cmp:('a ‑> 'a ‑> int) ‑> 'a list ‑> 'a list
val merge : cmp:('a ‑> 'a ‑> int) ‑> 'a list ‑> 'a list ‑> 'a list
type 'a t = 'a list
val empty : 'a t

empty is [].

val is_empty : _ t ‑> bool

is_empty l returns true iff l = [].

val map : f:('a ‑> 'b) ‑> 'a t ‑> 'b t

Safe version of List.map.

val (>|=) : 'a t ‑> ('a ‑> 'b) ‑> 'b t

Infix version of map with reversed arguments.

val cons : 'a ‑> 'a t ‑> 'a t

cons x l is x::l.

val append : 'a t ‑> 'a t ‑> 'a t

Safe version of List.append. Concatenate two lists.

val cons_maybe : 'a option ‑> 'a t ‑> 'a t

cons_maybe (Some x) l is x :: l. cons_maybe None l is l.

val (@) : 'a t ‑> 'a t ‑> 'a t

Like append. Concatenate two lists.

val filter : f:('a ‑> bool) ‑> 'a t ‑> 'a t

Safe version of List.filter. 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.

val fold_right : ('a ‑> 'b ‑> 'b) ‑> 'a t ‑> 'b ‑> 'b

Safe version of fold_right. fold_right f [a1; ...; an] b is f a1 (f a2 (... (f an b) ...)). Not tail-recursive.

val fold_while : f:('a ‑> 'b ‑> 'a * [ `Stop | `Continue ]) ‑> init:'a ‑> 'b t ‑> 'a

Fold until a stop condition via ('a, `Stop) is indicated by the accumulator.

val fold_map : f:('acc ‑> 'a ‑> 'acc * 'b) ‑> init:'acc ‑> 'a list ‑> 'acc * 'b list

fold_map ~f ~init l is a fold_left-like function, but it also maps the list to another list.

val scan_left : f:('acc ‑> 'a ‑> 'acc) ‑> init:'acc ‑> 'a list ‑> 'acc list
val fold_map2 : f:('acc ‑> 'a ‑> 'b ‑> 'acc * 'c) ‑> init:'acc ‑> 'a list ‑> 'b list ‑> 'acc * 'c list

fold_map2 is to fold_map what List.map2 is to List.map.

val fold_filter_map : f:('acc ‑> 'a ‑> 'acc * 'b option) ‑> init:'acc ‑> 'a list ‑> 'acc * 'b list

fold_filter_map ~f ~init l is a fold_left-like function, but also generates a list of output in a way similar to filter_map.

val fold_flat_map : f:('acc ‑> 'a ‑> 'acc * 'b list) ‑> init:'acc ‑> 'a list ‑> 'acc * 'b list

fold_flat_map f acc l is a fold_left-like function, but it also maps the list to a list of lists that is then flatten'd.

val count : f:('a ‑> bool) ‑> 'a list ‑> int
val init : int ‑> f:(int ‑> 'a) ‑> 'a t

init len ~f is f 0; f 1; ...; f (len-1).

val combine : 'a list ‑> 'b list ‑> ('a * 'b) list
val combine_gen : 'a list ‑> 'b list ‑> ('a * 'b) gen
val split : ('a * 'b) t ‑> 'a t * 'b t
val compare : ('a ‑> 'a ‑> int) ‑> 'a t ‑> 'a t ‑> int
val compare_lengths : 'a t ‑> 'b t ‑> int
val compare_length_with : 'a t ‑> int ‑> int
val equal : ('a ‑> 'a ‑> bool) ‑> 'a t ‑> 'a t ‑> bool
val flat_map : f:('a ‑> 'b t) ‑> 'a t ‑> 'b t

Map and flatten at the same time (safe). Evaluation order is not guaranteed.

val flatten : 'a t t ‑> 'a t

Safe flatten. Concatenate a list of lists.

val product : f:('a ‑> 'b ‑> 'c) ‑> 'a t ‑> 'b t ‑> 'c t

Cartesian product of the two lists, with the given combinator.

val fold_product : f:('c ‑> 'a ‑> 'b ‑> 'c) ‑> init:'c ‑> 'a t ‑> 'b t ‑> 'c

Fold on the cartesian product.

val cartesian_product : 'a t t ‑> 'a t t
val map_product_l : f:('a ‑> 'b list) ‑> 'a list ‑> 'b list list
val diagonal : 'a t ‑> ('a * 'a) t

All pairs of distinct positions of the list. list_diagonal l will return the list of List.nth i l, List.nth j l if i < j.

val partition_map : f:('a ‑> [< `Left of 'b | `Right of 'c | `Drop ]) ‑> 'a list ‑> 'b list * 'c list

partition_map ~f l maps f on l and gather results in lists:

val sublists_of_len : ?⁠last:('a list ‑> 'a list option) ‑> ?⁠offset:int ‑> len:int ‑> 'a list ‑> 'a list list

sublists_of_len n l returns sub-lists of l that have length n. By default, these sub-lists are non overlapping: sublists_of_len 2 [1;2;3;4;5;6] returns [1;2]; [3;4]; [5;6].

See CCList.sublists_of_len for more details.

val intersperse : x:'a ‑> 'a list ‑> 'a list

Insert the first argument between every element of the list.

val interleave : 'a list ‑> 'a list ‑> 'a list

interleave [x1…xn] [y1…ym] is x1,y1,x2,y2,… and finishes with the suffix of the longest list.

val pure : 'a ‑> 'a t

pure is return.

val (<*>) : ('a ‑> 'b) t ‑> 'a t ‑> 'b t

funs <*> l is product fun f x -> f x) funs l.

val (<$>) : ('a ‑> 'b) ‑> 'a t ‑> 'b t

(<$>) is map.

val return : 'a ‑> 'a t

return x is x.

val (>>=) : 'a t ‑> ('a ‑> 'b t) ‑> 'b t

l >>= f is flat_map f l.

val take : int ‑> 'a t ‑> 'a t

Take the n first elements, drop the rest.

val drop : int ‑> 'a t ‑> 'a t

Drop the n first elements, keep the rest.

val hd_tl : 'a t ‑> 'a * 'a t

hd_tl (x :: l) returns hd, l.

val take_drop : int ‑> 'a t ‑> 'a t * 'a t

take_drop n l returns l1, l2 such that l1 @ l2 = l and length l1 = min (length l) n.

val take_while : f:('a ‑> bool) ‑> 'a t ‑> 'a t

take_while ~f l returns the longest prefix of l for which f is true.

val drop_while : f:('a ‑> bool) ‑> 'a t ‑> 'a t

drop_while ~f l drops the longest prefix of l for which f is true.

val take_drop_while : f:('a ‑> bool) ‑> 'a t ‑> 'a t * 'a t
val last : int ‑> 'a t ‑> 'a t

last n l takes the last n elements of l (or less if l doesn't have that many elements).

val head_opt : 'a t ‑> 'a option

First element.

val tail_opt : 'a t ‑> 'a t option

Return the given list without its first element.

val last_opt : 'a t ‑> 'a option

Last element.

val find_pred : f:('a ‑> bool) ‑> 'a t ‑> 'a option

find_pred p l finds the first element of l that satisfies p, or returns None if no element satisfies p.

val find_opt : f:('a ‑> bool) ‑> 'a t ‑> 'a option
val find_pred_exn : f:('a ‑> bool) ‑> 'a t ‑> 'a

Unsafe version of find_pred.

val find_map : f:('a ‑> 'b option) ‑> 'a t ‑> 'b option

find_map ~f l traverses l, applying f to each element. If for some element x, f x = Some y, then Some y is returned. Otherwise the call returns None.

val find_mapi : f:(int ‑> 'a ‑> 'b option) ‑> 'a t ‑> 'b option

Like find_map, but also pass the index to the predicate function.

val find_idx : f:('a ‑> bool) ‑> 'a t ‑> (int * 'a) option

find_idx p x returns Some (i,x) where x is the i-th element of l, and p x holds. Otherwise returns None.

val remove : eq:('a ‑> 'a ‑> bool) ‑> key:'a ‑> 'a t ‑> 'a t

remove ~key l removes every instance of key from l. Tail-recursive.

val filter_map : f:('a ‑> 'b option) ‑> 'a t ‑> 'b t

filter_map ~f l is the sublist of l containing only elements for which f returns Some e. Map and remove elements at the same time.

val keep_some : 'a option t ‑> 'a t
val keep_ok : ('a, _) Result.result t ‑> 'a t
val all_some : 'a option t ‑> 'a t option
val all_ok : ('a, 'err) Result.result t ‑> ('a t, 'err) Result.result
val sorted_merge : cmp:('a ‑> 'a ‑> int) ‑> 'a list ‑> 'a list ‑> 'a list

Merges elements from both sorted list.

val sort_uniq : cmp:('a ‑> 'a ‑> int) ‑> 'a list ‑> 'a list

Sort the list and remove duplicate elements.

val sorted_merge_uniq : cmp:('a ‑> 'a ‑> int) ‑> 'a list ‑> 'a list ‑> 'a list

sorted_merge_uniq l1 l2 merges the sorted lists l1 and l2 and removes duplicates.

val is_sorted : cmp:('a ‑> 'a ‑> int) ‑> 'a list ‑> bool

is_sorted l returns true iff l is sorted (according to given order).

val sorted_insert : cmp:('a ‑> 'a ‑> int) ‑> ?⁠uniq:bool ‑> 'a ‑> 'a list ‑> 'a list

sorted_insert x l inserts x into l such that, if l was sorted, then sorted_insert x l is sorted too.

val uniq_succ : eq:('a ‑> 'a ‑> bool) ‑> 'a list ‑> 'a list

uniq_succ l removes duplicate elements that occur one next to the other. Examples: uniq_succ [1;2;1] = [1;2;1]. uniq_succ [1;1;2] = [1;2].

val group_succ : eq:('a ‑> 'a ‑> bool) ‑> 'a list ‑> 'a list list

group_succ ~eq l groups together consecutive elements that are equal according to eq.

Indices

val mapi : f:(int ‑> 'a ‑> 'b) ‑> 'a t ‑> 'b t

Like 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.

val iteri : f:(int ‑> 'a ‑> unit) ‑> 'a t ‑> unit

Like 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.

val iteri2 : f:(int ‑> 'a ‑> 'b ‑> unit) ‑> 'a t ‑> 'b t ‑> unit
val foldi : f:('b ‑> int ‑> 'a ‑> 'b) ‑> init:'b ‑> 'a t ‑> 'b

Like fold but it also passes in the index of each element to the folded function. Tail-recursive.

val foldi2 : f:('c ‑> int ‑> 'a ‑> 'b ‑> 'c) ‑> init:'c ‑> 'a t ‑> 'b t ‑> 'c
val get_at_idx : int ‑> 'a t ‑> 'a option

Get by index in the list. If the index is negative, it will get element starting from the end of the list.

val nth_opt : 'a t ‑> int ‑> 'a option
val get_at_idx_exn : int ‑> 'a t ‑> 'a

Get the i-th element, or

val set_at_idx : int ‑> 'a ‑> 'a t ‑> 'a t

Set i-th element (removes the old one), or does nothing if index is too high. If the index is negative, it will set element starting from the end of the list.

val insert_at_idx : int ‑> 'a ‑> 'a t ‑> 'a t

Insert at i-th position, between the two existing elements. If the index is too high, append at the end of the list. If the index is negative, it will insert element starting from the end of the list.

val remove_at_idx : int ‑> 'a t ‑> 'a t

Remove element at given index. Does nothing if the index is too high. If the index is negative, it will remove element starting from the end of the list.

Set Operators

Those operations maintain the invariant that the list does not contain duplicates (if it already satisfies it).

val add_nodup : eq:('a ‑> 'a ‑> bool) ‑> 'a ‑> 'a t ‑> 'a t

add_nodup x set adds x to set if it was not already present. Linear time.

val remove_one : eq:('a ‑> 'a ‑> bool) ‑> 'a ‑> 'a t ‑> 'a t

remove_one x set removes one occurrence of x from set. Linear time.

val mem : eq:('a ‑> 'a ‑> bool) ‑> 'a ‑> 'a t ‑> bool

Membership to the list. Linear time.

val subset : eq:('a ‑> 'a ‑> bool) ‑> 'a t ‑> 'a t ‑> bool

Test for inclusion.

val uniq : eq:('a ‑> 'a ‑> bool) ‑> 'a t ‑> 'a t

Remove duplicates w.r.t the equality predicate. Complexity is quadratic in the length of the list, but the order of elements is preserved. If you wish for a faster de-duplication but do not care about the order, use sort_uniq.

val union : eq:('a ‑> 'a ‑> bool) ‑> 'a t ‑> 'a t ‑> 'a t

List union. Complexity is product of length of inputs.

val inter : eq:('a ‑> 'a ‑> bool) ‑> 'a t ‑> 'a t ‑> 'a t

List intersection. Complexity is product of length of inputs.

Other Constructors

val range_by : step:int ‑> int ‑> int ‑> int t

range_by ~step i j iterates on integers from i to j included, where the difference between successive elements is step. use a negative step for a decreasing list.

val range : int ‑> int ‑> int t

range i j iterates on integers from i to j included. It works both for decreasing and increasing ranges.

val range' : int ‑> int ‑> int t

Like range but the second bound is excluded. For instance range' 0 5 = [0;1;2;3;4].

val (--) : int ‑> int ‑> int t

Infix alias for range.

val (--^) : int ‑> int ‑> int t

Infix alias for range'.

val replicate : int ‑> 'a ‑> 'a t

Replicate the given element n times.

val repeat : int ‑> 'a t ‑> 'a t

Concatenate the list with itself n times.

Association Lists

module Assoc : sig ... end
val assoc : eq:('a ‑> 'a ‑> bool) ‑> 'a ‑> ('a * 'b) t ‑> 'b

Like Assoc.get_exn.

val assoc_opt : eq:('a ‑> 'a ‑> bool) ‑> 'a ‑> ('a * 'b) t ‑> 'b option

Like Assoc.get.

val assq_opt : 'a ‑> ('a * 'b) t ‑> 'b option

Safe version of assq.

val mem_assoc : eq:('a ‑> 'a ‑> bool) ‑> 'a ‑> ('a * _) t ‑> bool

Like Assoc.mem.

val remove_assoc : eq:('a ‑> 'a ‑> bool) ‑> 'a ‑> ('a * 'b) t ‑> ('a * 'b) t

Like Assoc.remove.

References on Lists

module Ref : sig ... end
module type MONAD : sig ... end

Monadic Operations

module Traverse : functor (M : MONAD) -> sig ... end

Conversions

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
val random_choose : 'a t ‑> 'a random_gen

Randomly choose an element in the list.

val random_sequence : 'a random_gen t ‑> 'a t random_gen
val to_seq : 'a t ‑> 'a sequence

Return a sequence of the elements of the list.

val of_seq : 'a sequence ‑> 'a t

Build a list from a given sequence.

val to_gen : 'a t ‑> 'a gen

Return a gen of the elements of the list.

val of_gen : 'a gen ‑> 'a t

Build a list from a given gen.

val to_klist : 'a t ‑> 'a klist

Return a klist of the elements of the list.

val of_klist : 'a klist ‑> 'a t

Build a list from a given klist.

Infix Operators

It is convenient to open CCList.Infix to access the infix operators without cluttering the scope too much.

module Infix : sig ... end

IO

val pp : ?⁠start:string ‑> ?⁠stop:string ‑> ?⁠sep:string ‑> 'a printer ‑> 'a t printer

Print the contents of a list.