Set
A immutable sorted set module which allows customize compare behavior. The implementation uses balanced binary trees, and therefore searching and insertion take time logarithmic in the size of the map.
It also has three specialized inner modules Belt.Set.Int, Belt.Set.String and Belt.Set.Dict - This module separates data from function which is more verbose but slightly more efficient
RESmodule PairComparator =
Belt.Id.MakeComparable({
type t = (int, int)
let cmp = ((a0, a1), (b0, b1)) =>
switch (Pervasives.compare(a0, b0)) {
| 0 => Pervasives.compare(a1, b1)
| c => c
}
})
let mySet = Belt.Set.make(~id=module(PairComparator))
let mySet2 = Belt.Set.add(mySet, (1, 2))
Note: This module's examples will assume a predeclared module for integers
called IntCmp
. It is declared like this:
RESmodule IntCmp =
Belt.Id.MakeComparable({
type t = int
let cmp = Pervasives.compare
})
t
REStype t<'value, 'identity>
'value
is the element type
'identity
the identity of the collection
id
REStype id<'value, 'id> = Belt_Id.comparable<'value, 'id>
The identity needed for making a set from scratch
make
let make: (~id: id<'value, 'id>) => t<'value, 'id>
Creates a new set by taking in the comparator
RESlet set = Belt.Set.make(~id=module(IntCmp))
fromArray
let fromArray: (array<'value>, ~id: id<'value, 'id>) => t<'value, 'id>
Creates new set from array of elements.
RESlet s0 = Belt.Set.fromArray([1, 3, 2, 4], ~id=module(IntCmp))
s0->Belt.Set.toArray /* [1, 2, 3, 4] */
fromSortedArrayUnsafe
let fromSortedArrayUnsafe: (array<'value>, ~id: id<'value, 'id>) => t<'value, 'id>
The same as [fromArray][#fromarray] except it is after assuming the input array is already sorted.
isEmpty
let isEmpty: t<'a, 'b> => bool
Checks if set is empty.
RESlet empty = Belt.Set.fromArray([], ~id=module(IntCmp))
let notEmpty = Belt.Set.fromArray([1],~id=module(IntCmp))
Belt.Set.isEmpty(empty) /* true */
Belt.Set.isEmpty(notEmpty) /* false */
has
let has: (t<'value, 'id>, 'value) => bool
Checks if element exists in set.
RESlet set = Belt.Set.fromArray([1, 4, 2, 5], ~id=module(IntCmp))
set->Belt.Set.has(3) /* false */
set->Belt.Set.has(1) /* true */
add
let add: (t<'value, 'id>, 'value) => t<'value, 'id>
Adds element to set. If element existed in set, value is unchanged.
RESlet s0 = Belt.Set.make(~id=module(IntCmp))
let s1 = s0->Belt.Set.add(1)
let s2 = s1->Belt.Set.add(2)
let s3 = s2->Belt.Set.add(2)
s0->Belt.Set.toArray /* [] */
s1->Belt.Set.toArray /* [1] */
s2->Belt.Set.toArray /* [1, 2] */
s3->Belt.Set.toArray /* [1,2 ] */
s2 == s3 /* true */
mergeMany
let mergeMany: (t<'value, 'id>, array<'value>) => t<'value, 'id>
Adds each element of array to set. Unlike add, the reference of return value might be changed even if all values in array already exist in set
RESlet set = Belt.Set.make(~id=module(IntCmp))
let newSet = set->Belt.Set.mergeMany([5, 4, 3, 2, 1])
newSet->Belt.Set.toArray /* [1, 2, 3, 4, 5] */
remove
let remove: (t<'value, 'id>, 'value) => t<'value, 'id>
Removes element from set. If element wasn't existed in set, value is unchanged.
RESlet s0 = Belt.Set.fromArray([2,3,1,4,5], ~id=module(IntCmp))
let s1 = s0->Belt.Set.remove(1)
let s2 = s1->Belt.Set.remove(3)
let s3 = s2->Belt.Set.remove(3)
s1->Belt.Set.toArray /* [2,3,4,5] */
s2->Belt.Set.toArray /* [2,4,5] */
s2 == s3 /* true */
removeMany
let removeMany: (t<'value, 'id>, array<'value>) => t<'value, 'id>
Removes each element of array from set. Unlike remove, the reference of return value might be changed even if any values in array not existed in set.
RESlet set = Belt.Set.fromArray([1, 2, 3, 4],~id=module(IntCmp))
let newSet = set->Belt.Set.removeMany([5, 4, 3, 2, 1])
newSet->Belt.Set.toArray /* [] */
union
let union: (t<'value, 'id>, t<'value, 'id>) => t<'value, 'id>
Returns union of two sets.
RESlet s0 = Belt.Set.fromArray([5,2,3,5,6], ~id=module(IntCmp))
let s1 = Belt.Set.fromArray([5,2,3,1,5,4], ~id=module(IntCmp))
let union = Belt.Set.union(s0, s1)
union->Belt.Set.toArray /* [1,2,3,4,5,6] */
intersect
let intersect: (t<'value, 'id>, t<'value, 'id>) => t<'value, 'id>
Returns intersection of two sets.
RESlet s0 = Belt.Set.fromArray([5,2,3,5,6], ~id=module(IntCmp))
let s1 = Belt.Set.fromArray([5,2,3,1,5,4], ~id=module(IntCmp))
let intersect = Belt.Set.intersect(s0, s1)
intersect->Belt.Set.toArray /* [2,3,5] */
diff
let diff: (t<'value, 'id>, t<'value, 'id>) => t<'value, 'id>
Returns elements from first set, not existing in second set.
RESlet s0 = Belt.Set.fromArray([5,2,3,5,6], ~id=module(IntCmp))
let s1 = Belt.Set.fromArray([5,2,3,1,5,4], ~id=module(IntCmp))
Belt.Set.toArray(Belt.Set.diff(s0, s1)) /* [6] */
Belt.Set.toArray(Belt.Set.diff(s1,s0)) /* [1,4] */
subset
let subset: (t<'value, 'id>, t<'value, 'id>) => bool
Checks if second set is subset of first set.
RESlet s0 = Belt.Set.fromArray([5,2,3,5,6], ~id=module(IntCmp))
let s1 = Belt.Set.fromArray([5,2,3,1,5,4], ~id=module(IntCmp))
let s2 = Belt.Set.intersect(s0, s1)
Belt.Set.subset(s2, s0) /* true */
Belt.Set.subset(s2, s1) /* true */
Belt.Set.subset(s1, s0) /* false */
cmp
let cmp: (t<'value, 'id>, t<'value, 'id>) => int
Total ordering between sets. Can be used as the ordering function for doing sets of sets. It compares size first and then iterates over each element following the order of elements.
eq
let eq: (t<'value, 'id>, t<'value, 'id>) => bool
Checks if two sets are equal.
RESlet s0 = Belt.Set.fromArray([5,2,3], ~id=module(IntCmp))
let s1 = Belt.Set.fromArray([3,2,5], ~id=module(IntCmp))
Belt.Set.eq(s0, s1) /* true */
forEachU
let forEachU: (t<'value, 'id>, (. 'value) => unit) => unit
Same as forEach but takes uncurried functon.
forEach
let forEach: (t<'value, 'id>, 'value => unit) => unit
Applies function f
in turn to all elements of set in increasing order.
RESlet s0 = Belt.Set.fromArray([5,2,3,5,6], ~id=module(IntCmp))
let acc = ref(list{})
s0->Belt.Set.forEach(x => {
acc := Belt.List.add(acc.contents, x)
})
acc /* [6,5,3,2] */
reduceU
let reduceU: (t<'value, 'id>, 'a, (. 'a, 'value) => 'a) => 'a
reduce
let reduce: (t<'value, 'id>, 'a, ('a, 'value) => 'a) => 'a
Applies function f
to each element of set in increasing order. Function f
has two parameters: the item from the set and an “accumulator”, which starts with a value of initialValue
. reduce
returns the final value of the accumulator.
RESlet s0 = Belt.Set.fromArray([5,2,3,5,6], ~id=module(IntCmp))
s0->Belt.Set.reduce(list{}, (acc, element) =>
acc->Belt.List.add(element)
) /* [6,5,3,2] */
everyU
let everyU: (t<'value, 'id>, (. 'value) => bool) => bool
every
let every: (t<'value, 'id>, 'value => bool) => bool
Checks if all elements of the set satisfy the predicate. Order unspecified.
RESlet isEven = x => mod(x, 2) == 0
let s0 = Belt.Set.fromArray([2,4,6,8], ~id=module(IntCmp))
s0->Belt.Set.every(isEven) /* true */
someU
let someU: (t<'value, 'id>, (. 'value) => bool) => bool
some
let some: (t<'value, 'id>, 'value => bool) => bool
Checks if at least one element of the set satisfies the predicate.
RESlet isOdd = x => mod(x, 2) != 0
let s0 = Belt.Set.fromArray([1,2,4,6,8], ~id=module(IntCmp))
s0->Belt.Set.some(isOdd) /* true */
keepU
let keepU: (t<'value, 'id>, (. 'value) => bool) => t<'value, 'id>
keep
let keep: (t<'value, 'id>, 'value => bool) => t<'value, 'id>
Returns the set of all elements that satisfy the predicate.
RESlet isEven = x => mod(x, 2) == 0
let s0 = Belt.Set.fromArray([1,2,3,4,5], ~id=module(IntCmp))
let s1 = s0->Belt.Set.keep(isEven)
s1->Belt.Set.toArray /* [2,4] */
partitionU
let partitionU: (t<'value, 'id>, (. 'value) => bool) => (t<'value, 'id>, t<'value, 'id>)
partition
let partition: (t<'value, 'id>, 'value => bool) => (t<'value, 'id>, t<'value, 'id>)
Returns a pair of sets, where first is the set of all the elements of set that satisfy the predicate, and second is the set of all the elements of set that do not satisfy the predicate.
RESlet isOdd = x => mod(x, 2) != 0
let s0 = Belt.Set.fromArray([1,2,3,4,5], ~id=module(IntCmp))
let (s1, s2) = s0->Belt.Set.partition(isOdd)
s1->Belt.Set.toArray /* [1,3,5] */
s2->Belt.Set.toArray /* [2,4] */
size
let size: t<'value, 'id> => int
Returns size of the set.
RESlet s0 = Belt.Set.fromArray([1,2,3,4], ~id=module(IntCmp))
s0->Belt.Set.size /* 4 */
toArray
let toArray: t<'value, 'id> => array<'value>
Returns array of ordered set elements.
RESlet s0 = Belt.Set.fromArray([3,2,1,5], ~id=module(IntCmp))
s0->Belt.Set.toArray /* [1,2,3,5] */
toList
let toList: t<'value, 'id> => list<'value>
Returns list of ordered set elements.
RESlet s0 = Belt.Set.fromArray([3,2,1,5], ~id=module(IntCmp))
s0->Belt.Set.toList /* [1,2,3,5] */
minimum
let minimum: t<'value, 'id> => option<'value>
Returns minimum value of the collection. None
if collection is empty.
RESlet s0 = Belt.Set.make(~id=module(IntCmp))
let s1 = Belt.Set.fromArray([3,2,1,5], ~id=module(IntCmp))
s0->Belt.Set.minimum /* None */
s1->Belt.Set.minimum /* Some(1) */
minUndefined
let minUndefined: t<'value, 'id> => Js.undefined<'value>
Returns minimum value of the collection. undefined
if collection is empty.
RESlet s0 = Belt.Set.make(~id=module(IntCmp))
let s1 = Belt.Set.fromArray([3,2,1,5], ~id=module(IntCmp))
s0->Belt.Set.minUndefined /* undefined */
s1->Belt.Set.minUndefined /* 1 */
maximum
Returns maximum value of the collection. None
if collection is empty.
RESlet s0 = Belt.Set.make(~id=module(IntCmp))
let s1 = Belt.Set.fromArray([3,2,1,5], ~id=module(IntCmp))
s0->Belt.Set.maximum /* None */
s1->Belt.Set.maximum /* Some(5) */
maxUndefined
let maxUndefined: t<'value, 'id> => Js.undefined<'value>
Returns maximum value of the collection. undefined
if collection is empty.
RESlet s0 = Belt.Set.make(~id=module(IntCmp))
let s1 = Belt.Set.fromArray([3,2,1,5], ~id=module(IntCmp))
s0->Belt.Set.maxUndefined /* undefined */
s1->Belt.Set.maxUndefined /* 5 */
get
let get: (t<'value, 'id>, 'value) => option<'value>
Returns the reference of the value which is equivalent to value using the comparator specifiecd by this collection. Returns None
if element does not exist.
RESlet s0 = Belt.Set.fromArray([1,2,3,4,5], ~id=module(IntCmp))
s0->Belt.Set.get(3) /* Some(3) */
s0->Belt.Set.get(20) /* None */
getUndefined
let getUndefined: (t<'value, 'id>, 'value) => Js.undefined<'value>
Same as get but returns undefined
when element does not exist.
getExn
let getExn: (t<'value, 'id>, 'value) => 'value
Same as get but raise when element does not exist.
split
let split: (t<'value, 'id>, 'value) => ((t<'value, 'id>, t<'value, 'id>), bool)
Returns a tuple ((smaller, larger), present)
, present
is true when element exist in set.
RESlet s0 = Belt.Set.fromArray([1,2,3,4,5], ~id=module(IntCmp))
let ((smaller, larger), present) = s0->Belt.Set.split(3)
present /* true */
smaller->Belt.Set.toArray /* [1,2] */
larger->Belt.Set.toArray /* [4,5] */
getData
let getData: t<'value, 'id> => Belt_SetDict.t<'value, 'id>
Advanced usage only
Returns the raw data (detached from comparator), but its type is still manifested, so that user can pass identity directly without boxing.
getId
let getId: t<'value, 'id> => id<'value, 'id>
Advanced usage only
Returns the identity of set.
packIdData
let packIdData: (~id: id<'value, 'id>, ~data: Belt_SetDict.t<'value, 'id>) => t<'value, 'id>
Advanced usage only
Returns the packed collection.