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Map

cameligo
val empty : ('key, 'value) map
jsligo
let empty: map<'key, 'value>

Create an empty map.

type move = [int, int];
type register = map<address, move>;

let empty: register = Map.empty;
cameligo
val literal : ('key * 'value) list -> ('key, 'value) map
jsligo
let literal: (input: list<['key, 'value]>) => map<'key, 'value>

Create a non-empty map.

let moves: register =
  Map.literal(list([
    [("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" as address), [1, 2]],
    [("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), [0, 3]]]));
cameligo
val find_opt : 'key -> ('key, 'value) map -> 'value option
jsligo
let find_opt : (key: 'key, map: map <'key, 'value>) => option <'value>

Retrieve a (option) value from a map with the given key. Returns None if the key is missing and the value otherwise.

let my_balance: option<move> =
  Map.find_opt(("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), moves);
cameligo
val update: 'key -> 'value option -> ('key, 'value) map -> ('key, 'value) map
jsligo
let update: (key: 'key, new_value: option<'value>, map: map<'key, 'value>) => map <'key, 'value>

Note: When None is used as a value, the key and associated value is removed from the map.

let updated_map : register =
  Map.update
    (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), Some ([4, 9]), moves);
cameligo
val get_and_update : 'key -> 'value option -> ('key, 'value) map -> 'value option * ('key, 'value) map
jsligo
let get_and_update : (key : 'key, value : option<'value>, map : map<'key, 'value>) => [option<'value>, map<'key, 'value>]

Similar to update but it also returns the value that was previously stored in the map.

let [old_move, updated_map2] : [option<move>, register] =
  Map.get_and_update (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), (Some([24, 48] as move)), moves);
cameligo
val add : 'key -> 'value -> ('key, 'value) map  -> ('key, 'value) map
jsligo
let add: (key: 'key, value: 'value, map: map<'key, 'value>) => map<'key, 'value>

Returns a new map with key-value pair added to the input map.

let add = (m: register): register =>
  Map.add
    (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), [4, 9], m);
cameligo
val remove : 'key -> ('key, 'value) map -> ('key, 'value) map
jsligo
let remove: ('key: key, map: map<'key, 'value>) => map<'key, 'value>

Returns a new map with key-value pair removed from the input map.

let updated_map3 : register =
  Map.remove (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), moves);
cameligo
val iter : ('key * 'value -> unit) -> ('key, 'value) map -> unit
jsligo
let iter: (iter: (['key, 'value]) => unit, map: map<'key, 'value>) => unit

Iterate over key-value pairs in a map.

let iter_op = (m : register) : unit => {
  let predicate = ([i, j]: [address, move]): unit => assert (j[0] > 3);
  Map.iter (predicate, m);
};
cameligo
val map : ('key * 'value -> 'new_value) -> ('key, 'value) map -> ('key, 'new_value) map
jsligo
let map: (mapper: (item: ['key, 'value]) => 'new_value, map: map<'key, 'value>) => map<'key, 'new_value>

Applies the mapper function on the key-value pairs of map and builds a new map

let map_op = (m : register) : register => {
  let increment = ([_i, j]: [address, move]) : move => [j[0], j[1] + 1];
  return Map.map (increment, m);
};
cameligo
val fold : ('acc * ('key * 'value) -> 'acc) -> ('key, 'value) map -> 'acc -> 'acc
jsligo
let fold: (iter: ((acc: 'acc, item: ['key, 'value]) => 'acc), map: map<'key, 'value>, acc: 'acc) => 'acc

Fold over key-value pairs in a map:

let fold_op = (m : register): int => {
  let folded = ([i, j]: [int, [address, move]]):int => i + j[1][1];
  return Map.fold (folded, m, 5);
};
cameligo
val size : ('key, 'value) map -> nat
jsligo
let size: (map: map<'key, 'value>) => nat

Return the number of items in the map:

let _ : nat = Map.size(moves);
cameligo
val mem : 'key -> ('key, 'value) map -> bool
jsligo
let mem : (key: 'key, map: map<'key, 'value>) => bool

Checks if a key exists in the map:

let found : bool = Map.mem (("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" as address),  moves);
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