sets

Functions for Set Manipulation

Sets are collections of elements with no duplicate elements. The representation of a set is not defined.

This module provides exactly the same interface as the module `ordsets` but with a defined 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 (`==`).

As returned by `new/0`.

new/0

Returns a new empty set.

is_set/1

Returns `true` if `Set` is a set of elements, otherwise `false`.

size/1

Returns the number of elements in `Set`.

to_list/1

Returns the elements of `Set` as a list.

from_list/1

Returns an set of the elements in `List`.

is_element/2

Returns `true` if `Element` is an element of `Set`, otherwise `false`.

Returns a new set formed from `Set1` with `Element` inserted.

del_element/2

Returns `Set1`, but with `Element` removed.

union/2

Returns the merged (union) set of `Set1` and `Set2`.

union/1

Returns the merged (union) set of the list of sets.

intersection/2

Returns the intersection of `Set1` and `Set2`.

intersection/1

Returns the intersection of the non-empty list of sets.

is_disjoint/2

Returns `true` if `Set1` and `Set2` are disjoint (have no elements in common), and `false` otherwise.

subtract/2

Returns only the elements of `Set1` which are not also elements of `Set2`.

is_subset/2

Returns `true` when every element of `Set1`1 is also a member of `Set2`, otherwise `false`.

fold/3

Fold `Function` over every element in `Set` returning the final value of the accumulator.

filter/2

Filter elements in `Set1` with boolean function `Pred`.