Module List


module List = struct ... end 
Functions

length : 'a list -> int
Return the length (number of elements) of the given list.

hd : 'b list -> 'b
Return the first element of the given list. Raise Failure "hd" if the list is empty.

tl : 'c list -> 'c list
Return the given list without its first element. Raise Failure "tl" if the list is empty.

nth : 'd list -> int -> 'd
Return the 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.

rev : 'e list -> 'e list
List reversal.

append : 'f list -> 'f list -> 'f list
Catenate two lists. Same function as the infix operator @. Not tail-recursive (length of the first argument). The @ operator is not tail-recursive either.

rev_append : 'g list -> 'g list -> 'g list
List.rev_append l1 l2 reverses l1 and catenates it to l2. This is equivalent to List.rev l1 @ l2, but rev_append is tail-recursive and more efficient.

concat : 'h list list -> 'h list

flatten : 'i list list -> 'i list
Catenate (flatten) a list of lists. Not tail-recursive (length of the argument + length of the longest sub-list).

iter : f:('j -> unit) -> 'j list -> 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.

map : f:('k -> 'l) -> 'k list -> 'l list
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.

rev_map : f:('m -> 'n) -> 'm list -> 'n list
List.rev_map f l gives the same result as List.rev (List.map f l), but is tail-recursive and more efficient.

fold_left : f:('o -> 'p -> 'o) -> init:'o -> 'p list -> 'o
List.fold_left f a [b1; ...; bn] is f (... (f (f a b1) b2) ...) bn.

fold_right : f:('q -> 'r -> 'r) -> 'q list -> init:'r -> 'r
List.fold_right f [a1; ...; an] b is f a1 (f a2 (... (f an b) ...)). Not tail-recursive.

iter2 : f:('s -> 't -> unit) -> 's list -> 't list -> 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.

map2 : f:('u -> 'v -> 'w) -> 'u list -> 'v list -> 'w list
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.

rev_map2 : f:('x -> 'y -> 'z) -> 'x list -> 'y list -> 'z list
List.rev_map2 f l gives the same result as List.rev (List.map2 f l), but is tail-recursive and more efficient.

fold_left2 : f:('a1 -> 'b1 -> 'c1 -> 'a1) -> init:'a1 -> 'b1 list -> 'c1 list -> 'a1
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.

fold_right2 : f:('d1 -> 'e1 -> 'f1 -> 'f1) -> 'd1 list -> 'e1 list -> init:'f1 -> 'f1
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.

for_all : f:('g1 -> bool) -> 'g1 list -> 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).

exists : f:('h1 -> bool) -> 'h1 list -> 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).

for_all2 : f:('i1 -> 'j1 -> bool) -> 'i1 list -> 'j1 list -> bool

exists2 : f:('k1 -> 'l1 -> bool) -> 'k1 list -> 'l1 list -> bool
Same as for_all and exists, but for a two-argument predicate. Raise Invalid_argument if the two lists have different lengths.

mem : 'm1 -> 'm1 list -> bool
mem a l is true if and only if a is equal to an element of l.

memq : 'n1 -> 'n1 list -> bool
Same as mem, but uses physical equality instead of structural equality to compare list elements.

find : f:('o1 -> bool) -> 'o1 list -> 'o1
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.

filter : f:('p1 -> bool) -> 'p1 list -> 'p1 list

find_all : f:('q1 -> bool) -> 'q1 list -> 'q1 list
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. find_all is another name for filter.

partition : f:('r1 -> bool) -> 'r1 list -> 'r1 list * 'r1 list
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.

assoc : 's1 -> ('s1 * 't1) list -> 't1
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.

assq : 'u1 -> ('u1 * 'v1) list -> 'v1
Same as assoc, but uses physical equality instead of structural equality to compare keys.

mem_assoc : 'w1 -> ('w1 * 'x1) list -> bool
Same as assoc, but simply return true if a binding exists, and false if no bindings exist for the given key.

mem_assq : 'y1 -> ('y1 * 'z1) list -> bool
Same as mem_assoc, but uses physical equality instead of structural equality to compare keys.

remove_assoc : 'a2 -> ('a2 * 'b2) list -> ('a2 * 'b2) list
remove_assoc a l returns the list of pairs l without the first pair with key a, if any. Not tail-recursive.

remove_assq : 'c2 -> ('c2 * 'd2) list -> ('c2 * 'd2) list
Same as remove_assq, but uses physical equality instead of structural equality to compare keys. Not tail-recursive.

split : ('e2 * 'f2) list -> 'e2 list * 'f2 list
Transform a list of pairs into a pair of lists: split [(a1,b1); ...; (an,bn)] is ([a1; ...; an], [b1; ...; bn]). Not tail-recursive.

combine : 'g2 list -> 'h2 list -> ('g2 * 'h2) list
Transform a pair of lists into a list of pairs: combine ([a1; ...; an], [b1; ...; bn]) is [(a1,b1); ...; (an,bn)]. Raise Invalid_argument if the two lists have different lengths. Not tail-recursive.

sort : cmp:('i2 -> 'i2 -> int) -> 'i2 list -> 'i2 list
Sort a list in increasing order according to a comparison function. The comparison function must return 0 if it arguments compare as equal, a positive integer if the first is greater, and a negative integer if the first is smaller. For example, the compare function 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 and is the same as List.stable_sort.

stable_sort : cmp:('j2 -> 'j2 -> int) -> 'j2 list -> 'j2 list
Same as List.sort, but the sorting algorithm is stable.
The current implementation is Merge Sort. It runs in constant heap space and logarithmic stack space.