extlib
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type ('a, 'b) t = ('a, 'b) Hashtbl.t

The type of a hashtable.

New Functions
val exists : ('a, 'b) t -> 'a -> bool

exists h k returns true is at least one item with key k is found in the hashtable.

val keys : ('a, 'b) t -> 'a Enum.t

Return an enumeration of all the keys of a hashtable. If the key is in the Hashtable multiple times, all occurrences will be returned.

val values : ('a, 'b) t -> 'b Enum.t

Return an enumeration of all the values of a hashtable.

val enum : ('a, 'b) t -> ('a * 'b) Enum.t

Return an enumeration of (key,value) pairs of a hashtable.

val of_enum : ('a * 'b) Enum.t -> ('a, 'b) t

Create a hashtable from a (key,value) enumeration.

val find_default : ('a, 'b) t -> 'a -> 'b -> 'b

Find a binding for the key, and return a default value if not found

val find_opt : ('a, 'b) Hashtbl.t -> 'a -> 'b option

Find a binding for the key, or return None if no value is found

val find_option : ('a, 'b) Hashtbl.t -> 'a -> 'b option

compatibility, use find_opt

val remove_all : ('a, 'b) t -> 'a -> unit

Remove all bindings for the given key

val map : ('b -> 'c) -> ('a, 'b) t -> ('a, 'c) t

map f x creates a new hashtable with the same keys as x, but with the function f applied to all the values

val length : ('a, 'b) t -> int

Return the number of elements inserted into the Hashtbl (including duplicates)

val reset : ('a, 'b) t -> unit
val randomize : unit -> unit
type statistics = Hashtbl.statistics = {
  1. num_bindings : int;
  2. num_buckets : int;
  3. max_bucket_length : int;
  4. bucket_histogram : int array;
}
val stats : ('a, 'b) t -> statistics
val seeded_hash_param : int -> int -> int -> 'a -> int
val seeded_hash : int -> 'a -> int
val is_randomized : unit -> bool
val filter_map_inplace : ('a -> 'b -> 'b option) -> ('a, 'b) t -> unit
Older Functions

Please refer to the Ocaml Manual for documentation of these functions.

val create : ?random:bool -> int -> ('a, 'b) t
  • before 4.00.0

    random is ignored

val clear : ('a, 'b) t -> unit
val add : ('a, 'b) t -> 'a -> 'b -> unit
val copy : ('a, 'b) t -> ('a, 'b) t
val find : ('a, 'b) t -> 'a -> 'b
val find_all : ('a, 'b) t -> 'a -> 'b list
val mem : ('a, 'b) t -> 'a -> bool
val remove : ('a, 'b) t -> 'a -> unit
val replace : ('a, 'b) t -> 'a -> 'b -> unit
val iter : ('a -> 'b -> unit) -> ('a, 'b) t -> unit
val fold : ('a -> 'b -> 'c -> 'c) -> ('a, 'b) t -> 'c -> 'c
val hash : 'a -> int
val hash_param : int -> int -> 'a -> int
val to_seq : ('a, 'b) t -> ('a * 'b) Seq.t

*_seq functions were introduced in OCaml 4.07.0, and are _not_ implemented in extlib for older OCaml versions

val to_seq_keys : ('a, _) t -> 'a Seq.t
val to_seq_values : (_, 'b) t -> 'b Seq.t
val add_seq : ('a, 'b) t -> ('a * 'b) Seq.t -> unit
val replace_seq : ('a, 'b) t -> ('a * 'b) Seq.t -> unit
val of_seq : ('a * 'b) Seq.t -> ('a, 'b) t
val rebuild : ?random:bool -> ('a, 'b) t -> ('a, 'b) t

Functor interface forwards directly to stdlib implementation (i.e. no enum functions)

module type HashedType = Hashtbl.HashedType
module type S = Hashtbl.S
module Make = Hashtbl.Make
module type SeededHashedType = Hashtbl.SeededHashedType
module type SeededS = Hashtbl.SeededS
module MakeSeeded = Hashtbl.MakeSeeded