Module
sets
Module Summary
Functions for set manipulation.
Description
Sets are collections of elements with no duplicate elements. The representation of a set is undefined.
This module provides the same interface as the ordsets(3) module but with an undefined representation. One difference is that while this module considers two elements as different if they do not match (=:=), ordsets considers two elements as different if and only if they do not compare equal (==).
Erlang/OTP 24.0 introduced a new internal representation for sets which is more performant. Developers can use this new representation by passing the {version, 2} flag to new/1 and from_list/2, such as sets:new([{version, 2}]). This new representation will become the default in future Erlang/OTP versions. Functions that work on two sets, such as union/2 and similar, will work with sets of different versions. In such cases, there is no guarantee about the version of the returned set. Explicit conversion from the old version to the new one can be done with sets:from_list(sets:to_list(Old), [{version,2}]).
Exports
add_element(Element, Set1) -> Set2 |
Types
Returns a new set formed from Set1 with Element inserted.
del_element(Element, Set1) -> Set2 |
Types
Returns Set1, but with Element removed.
filter(Pred, Set1) -> Set2 |
Types
Filters elements in Set1 with boolean function Pred.
fold(Function, Acc0, Set) -> Acc1 |
Types
Folds Function over every element in Set and returns the final value of the accumulator. The evaluation order is undefined.
from_list(List) -> Set |
Types
Returns a set of the elements in List.
from_list(List, Opts :: [{version, 1..2}]) -> Set | OTP 24.0 |
Types
Returns a set of the elements in List at the given version.
intersection(SetList) -> Set |
Types
Returns the intersection of the non-empty list of sets.
intersection(Set1, Set2) -> Set3 |
Types
Returns the intersection of Set1 and Set2.
is_disjoint(Set1, Set2) -> boolean() |
Types
Returns true if Set1 and Set2 are disjoint (have no elements in common), otherwise false.
is_element(Element, Set) -> boolean() |
Types
Returns true if Element is an element of Set, otherwise false.
is_empty(Set) -> boolean() | OTP 21.0 |
Types
Returns true if Set is an empty set, otherwise false.
is_set(Set) -> boolean() |
Types
Returns true if Set is a set of elements, otherwise false.
is_subset(Set1, Set2) -> boolean() |
Types
Returns true when every element of Set1 is also a member of Set2, otherwise false.
new() -> set() |
Returns a new empty set.
new(Opts :: [{version, 1..2}]) -> set() | OTP 24.0 |
Returns a new empty set at the given version.
size(Set) -> integer() >= 0 |
Types
Returns the number of elements in Set.
subtract(Set1, Set2) -> Set3 |
Types
Returns only the elements of Set1 that are not also elements of Set2.
to_list(Set) -> List |
Types
Returns the elements of Set as a list. The order of the returned elements is undefined.
union(SetList) -> Set |
Types
Returns the merged (union) set of the list of sets.
union(Set1, Set2) -> Set3 |
Types
Returns the merged (union) set of Set1 and Set2.
See Also
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Licensed under the Apache License, Version 2.0.