Creates a map from an association list with possibly repeated keys. The values in the map for a given key appear in the same order as they did in the association list.
val of_alist_fold :
('a, 'cmp)Comparator.Module.t->('a * 'b) list->init:'c->f:('c->'b->'c)->('a, 'c, 'cmp)t
Combines an association list into a map, folding together bound values with common keys. The accumulator is per-key.
val of_alist_reduce :
('a, 'cmp)Comparator.Module.t->('a * 'b) list->f:('b->'b->'b)->('a, 'b, 'cmp)t
Combines an association list into a map, reducing together bound values with common keys.
val of_iteri :
('a, 'cmp)Comparator.Module.t->iteri:(f:(key:'a->data:'b-> unit)-> unit)->[ `Ok of ('a, 'b, 'cmp)t| `Duplicate_key of 'a ]
of_iteri ~iteri behaves like of_alist, except that instead of taking a concrete data structure, it takes an iteration function. For instance, to convert a string table into a map: of_iteri (module String) ~f:(Hashtbl.iteri table). It is faster than adding the elements one by one.
val of_iteri_exn :
('a, 'cmp)Comparator.Module.t->iteri:(f:(key:'a->data:'b-> unit)-> unit)->('a, 'b, 'cmp)t
Like of_iteri except that it raises an exception if duplicate 'a keys are found.
Creates a map from a sorted array of key-data pairs. The input array must be sorted (either in ascending or descending order), as given by the relevant comparator, and must not contain duplicate keys. If either of these conditions does not hold, an error is returned.
val of_sorted_array_unchecked :
('a, 'cmp)Comparator.Module.t->('a * 'b) array->('a, 'b, 'cmp)t
Like of_sorted_array except that it returns a map with broken invariants when an Error would have been returned.
of_increasing_iterator_unchecked c ~len ~f behaves like of_sorted_array_unchecked c
(Array.init len ~f), with the additional restriction that a decreasing order is not supported. The advantage is not requiring you to allocate an intermediate array. f will be called with 0, 1, ... len - 1, in order.
Creates a map from an association sequence with possibly repeated keys. The values in the map for a given key appear in the same order as they did in the association list.
of_sequence_multi c seq behaves like of_alist_exn c (Sequence.to_list seq) but does not allocate the intermediate list.
length map returns the number of elements in map. O(1), but Tree.length is O(n).
val set : ('k, 'v, 'cmp)t->key:'k->data:'v->('k, 'v, 'cmp)t
Returns a new map with the specified new binding; if the key was already bound, its previous binding disappears.
val add :
('k, 'v, 'cmp)t->key:'k->data:'v->('k, 'v, 'cmp)tOr_duplicate.t
add t ~key ~data adds a new entry to t mapping key to data and returns `Ok with the new map, or if key is already present in t, returns `Duplicate.
val add_exn : ('k, 'v, 'cmp)t->key:'k->data:'v->('k, 'v, 'cmp)t
val add_multi :
('k, 'v list, 'cmp)t->key:'k->data:'v->('k, 'v list, 'cmp)t
If key is not present then add a singleton list, otherwise, cons data onto the head of the existing list.
val remove_multi : ('k, 'v list, 'cmp)t->'k->('k, 'v list, 'cmp)t
If the key is present, then remove its head element; if the result is empty, remove the key.
val find_multi : ('k, 'v list, 'cmp)t->'k->'v list
Returns the value bound to the given key, or the empty list if there is none.
val change :
('k, 'v, 'cmp)t->'k->f:('v option->'v option)->('k, 'v, 'cmp)t
change t key ~f returns a new map m that is the same as t on all keys except for key, and whose value for key is defined by f, i.e., find m key = f (find
t key).
val update : ('k, 'v, 'cmp)t->'k->f:('v option->'v)->('k, 'v, 'cmp)t
update t key ~f is change t key ~f:(fun o -> Some (f o)).
Iterates until the first time f returns Stop. If f returns Stop, the final result is Unfinished. Otherwise, the final result is Finished.
val iter2 :
('k, 'v1, 'cmp)t->('k, 'v2, 'cmp)t->f:(key:'k->data:('v1, 'v2)Merge_element.t-> unit)->
unit
Iterates two maps side by side. The complexity of this function is O(M + N). If two inputs are [(0, a); (1, a)] and [(1, b); (2, b)], f will be called with [(0,
`Left a); (1, `Both (a, b)); (2, `Right b)].
val map : ('k, 'v1, 'cmp)t->f:('v1->'v2)->('k, 'v2, 'cmp)t
Returns a new map with bound values replaced by f applied to the bound values.
val mapi :
('k, 'v1, 'cmp)t->f:(key:'k->data:'v1->'v2)->('k, 'v2, 'cmp)t
Like map, but the passed function takes both key and data as arguments.
val map_keys :
('k2, 'cmp2)Comparator.Module.t->('k1, 'v, 'cmp1)t->f:('k1->'k2)->[ `Ok of ('k2, 'v, 'cmp2)t| `Duplicate_key of 'k2 ]
Convert map with keys of type 'k2 to a map with keys of type 'k2 using f.
val map_keys_exn :
('k2, 'cmp2)Comparator.Module.t->('k1, 'v, 'cmp1)t->f:('k1->'k2)->('k2, 'v, 'cmp2)t
Like map_keys, but raises on duplicate key.
val fold :
('k, 'v, _)t->init:'acc->f:(key:'k->data:'v->'acc->'acc)->'acc
Folds over keys and data in the map in increasing order of key.
val fold_until :
('k, 'v, _)t->init:'acc->f:(key:'k->data:'v->'acc->('acc, 'final)Container.Continue_or_stop.t)->finish:('acc->'final)->'final
Folds over keys and data in the map in increasing order of key, until the first time that f returns Stop _. If f returns Stop final, this function returns immediately with the value final. If f never returns Stop _, and the final call to f returns Continue last, this function returns finish last.
val fold_right :
('k, 'v, _)t->init:'acc->f:(key:'k->data:'v->'acc->'acc)->'acc
Folds over keys and data in the map in decreasing order of key.
val fold2 :
('k, 'v1, 'cmp)t->('k, 'v2, 'cmp)t->init:'acc->f:(key:'k->data:('v1, 'v2)Merge_element.t->'acc->'acc)->'acc
Folds over two maps side by side, like iter2.
val filter_keys : ('k, 'v, 'cmp)t->f:('k-> bool)->('k, 'v, 'cmp)t
filter, filteri, filter_keys, filter_map, and filter_mapi run in O(n) time.
filter, filteri, filter_keys, partition_tf and partitioni_tf keep a lot of sharing between their result and the original map. Dropping or keeping a run of k consecutive elements costs O(log(k)) extra memory. Keeping the entire map costs no extra memory at all: filter ~f:(fun _ -> true) returns the original map.
val filter : ('k, 'v, 'cmp)t->f:('v-> bool)->('k, 'v, 'cmp)t
val filteri :
('k, 'v, 'cmp)t->f:(key:'k->data:'v-> bool)->('k, 'v, 'cmp)t
val filter_map :
('k, 'v1, 'cmp)t->f:('v1->'v2 option)->('k, 'v2, 'cmp)t
Returns a new map with bound values filtered by f applied to the bound values.
val filter_mapi :
('k, 'v1, 'cmp)t->f:(key:'k->data:'v1->'v2 option)->('k, 'v2, 'cmp)t
Like filter_map, but the passed function takes both key and data as arguments.
Hash function: a building block to use when hashing data structures containing maps in them. hash_fold_direct hash_fold_key is compatible with compare_direct iff hash_fold_key is compatible with (comparator m).compare of the map m being hashed.
val equal : ('v->'v-> bool)->('k, 'v, 'cmp)t->('k, 'v, 'cmp)t-> bool
equal cmp m1 m2 tests whether the maps m1 and m2 are equal, that is, contain the same keys and associate each key with the same value. cmp is the equality predicate used to compare the values associated with the keys.
Merges two maps. The runtime is O(length(t1) + length(t2)). You shouldn't use this function to merge a list of maps; consider using merge_disjoin_exn or merge_skewed instead.
val merge_disjoint_exn :
('k, 'v, 'cmp)t->('k, 'v, 'cmp)t->('k, 'v, 'cmp)t
Merges two dictionaries with the same type of data and disjoint sets of keys. Raises if any keys overlap.
val merge_skewed :
('k, 'v, 'cmp)t->('k, 'v, 'cmp)t->combine:(key:'k->'v->'v->'v)->('k, 'v, 'cmp)t
A special case of merge, merge_skewed t1 t2 is a map containing all the bindings of t1 and t2. Bindings that appear in both t1 and t2 are combined into a single value using the combine function. In a call combine ~key v1 v2, the value v1 comes from t1 and v2 from t2.
The runtime of merge_skewed is O(min(l1, l2) * log(max(l1, l2))), where l1 is the length of t1 and l2 the length of t2. This is likely to be faster than merge when one of the maps is a lot smaller, or when you merge a list of maps.
symmetric_diff t1 t2 ~data_equal returns a list of changes between t1 and t2. It is intended to be efficient in the case where t1 and t2 share a large amount of structure. The keys in the output sequence will be in sorted order.
It is assumed that data_equal is at least as equating as physical equality: that phys_equal x y implies data_equal x y. Otherwise, symmetric_diff may behave in unexpected ways. For example, with ~data_equal:(fun _ _ -> false) it is NOT necessarily the case the resulting change sequence will contain an element (k, `Unequal _) for every key k shared by both maps.
Warning: Float equality violates this property! phys_equal Float.nan Float.nan is true, but Float.(=) Float.nan Float.nan is false.
val fold_symmetric_diff :
('k, 'v, 'cmp)t->('k, 'v, 'cmp)t->data_equal:('v->'v-> bool)->init:'acc->f:('acc->('k, 'v)Symmetric_diff_element.t->'acc)->'acc
fold_symmetric_diff t1 t2 ~data_equal folds across an implicit sequence of changes between t1 and t2, in sorted order by keys. Equivalent to Sequence.fold (symmetric_diff t1 t2 ~data_equal), and more efficient.
split t key returns a map of keys strictly less than key, the mapping of key if any, and a map of keys strictly greater than key.
Runtime is O(m + log n), where n is the size of the input map and m is the size of the smaller of the two output maps. The O(m) term is due to the need to calculate the length of the output maps.
split_le_gt t key returns a map of keys that are less or equal to key and a map of keys strictly greater than key.
Runtime is O(m + log n), where n is the size of the input map and m is the size of the smaller of the two output maps. The O(m) term is due to the need to calculate the length of the output maps.
split_lt_ge t key returns a map of keys strictly less than key and a map of keys that are greater or equal to key.
Runtime is O(m + log n), where n is the size of the input map and m is the size of the smaller of the two output maps. The O(m) term is due to the need to calculate the length of the output maps.
val append :
lower_part:('k, 'v, 'cmp)t->upper_part:('k, 'v, 'cmp)t->[ `Ok of ('k, 'v, 'cmp)t| `Overlapping_key_ranges ]
append ~lower_part ~upper_part returns `Ok map where map contains all the (key, value) pairs from the two input maps if all the keys from lower_part are less than all the keys from upper_part. Otherwise it returns `Overlapping_key_ranges.
Runtime is O(log n) where n is the size of the larger input map. This can be significantly faster than Map.merge or repeated Map.add.
subrange t ~lower_bound ~upper_bound returns a map containing all the entries from t whose keys lie inside the interval indicated by ~lower_bound and ~upper_bound. If this interval is empty, an empty map is returned.
Runtime is O(m + log n), where n is the size of the input map and m is the size of the output map. The O(m) term is due to the need to calculate the length of the output map.
val fold_range_inclusive :
('k, 'v, 'cmp)t->min:'k->max:'k->init:'acc->f:(key:'k->data:'v->'acc->'acc)->'acc
fold_range_inclusive t ~min ~max ~init ~f folds f (with initial value ~init) over all keys (and their associated values) that are in the range [min, max] (inclusive).
val range_to_alist : ('k, 'v, 'cmp)t->min:'k->max:'k->('k * 'v) list
range_to_alist t ~min ~max returns an associative list of the elements whose keys lie in [min, max] (inclusive), with the smallest key being at the head of the list.
closest_key t dir k returns the (key, value) pair in t with key closest to k that satisfies the given inequality bound.
For example, closest_key t `Less_than k would be the pair with the closest key to k where key < k.
to_sequence can be used to get the same results as closest_key. It is less efficient for individual lookups but more efficient for finding many elements starting at some value.
nth t n finds the (key, value) pair of rank n (i.e., such that there are exactly n keys strictly less than the found key), if one exists. O(log(length t) + n) time.
to_sequence ?order ?keys_greater_or_equal_to ?keys_less_or_equal_to t gives a sequence of key-value pairs between keys_less_or_equal_to and keys_greater_or_equal_to inclusive, presented in order. If keys_greater_or_equal_to > keys_less_or_equal_to, the sequence is empty.
When neither keys_greater_or_equal_to nor keys_less_or_equal_to are provided, the cost is O(log n) up front and amortized O(1) to produce each element. If either is provided (and is used by the order parameter provided), then the the cost is O(n) up front, and amortized O(1) to produce each element.
binary_search t ~compare which elt returns the (key, value) pair in t specified by compare and which, if one exists.
t must be sorted in increasing order according to compare, where compare and elt divide t into three (possibly empty) segments:
| < elt | = elt | > elt |
binary_search returns an element on the boundary of segments as specified by which. See the diagram below next to the which variants.
binary_search does not check that compare orders t, and behavior is unspecified if compare doesn't order t. Behavior is also unspecified if compare mutates t.
binary_search_segmented returns the (key, value) pair on the boundary of the segments as specified by which: `Last_on_left yields the last element of the left segment, while `First_on_right yields the first element of the right segment. It returns None if the segment is empty.
binary_search_segmented does not check that segment_of segments t as in the diagram, and behavior is unspecified if segment_of doesn't segment t. Behavior is also unspecified if segment_of mutates t.
val binary_search_subrange :
('k, 'v, 'cmp)t->compare:(key:'k->data:'v->'bound-> int)->lower_bound:'boundMaybe_bound.t->upper_bound:'boundMaybe_bound.t->('k, 'v, 'cmp)t
binary_search_subrange takes a compare function that divides t into three (possibly empty) segments with respect to lower_bound and upper_bound:
Runtime is O(log m + n) where m is the length of the input map and n is the length of the output. The linear term in n is to compute the length of the output.
Behavior is undefined if compare does not segment t as shown above, or if compare mutates its inputs.
Creates traversals to reconstruct a map within an applicative. Uses Lazy_applicative so that the map can be traversed within the applicative, rather than needing to be traversed all at once, outside the applicative.
Using_comparator is a similar interface as the toplevel of Map, except the functions take a ~comparator:('k, 'cmp) Comparator.t, whereas the functions at the toplevel of Map take a ('k, 'cmp) comparator.