
ordsets(3erl) Erlang Module Definition ordsets(3erl)
NAME
ordsets  Functions for Manipulating Sets as Ordered Lists
DESCRIPTION
Sets are collections of elements with no duplicate elements. An ordset is a representation
of a set, where an ordered list is used to store the elements of the set. An ordered list
is more efficient than an unordered list.
This module provides exactly the same interface as the module sets but with a defined rep
resentation. One difference is that while sets considers two elements as different if they
do not match ( =:= ), this module considers two elements as different if and only if they
do not compare equal ( == ).
DATA TYPES
ordered_set()
as returned by new/0
EXPORTS
new() > Ordset
Types Ordset = ordered_set()
Returns a new empty ordered set.
is_set(Ordset) > bool()
Types Ordset = term()
Returns true if Ordset is an ordered set of elements, otherwise false .
size(Ordset) > int()
Types Ordset = term()
Returns the number of elements in Ordset .
to_list(Ordset) > List
Types Ordset = ordered_set()
List = [term()]
Returns the elements of Ordset as a list.
from_list(List) > Ordset
Types List = [term()]
Ordset = ordered_set()
Returns an ordered set of the elements in List .
is_element(Element, Ordset) > bool()
Types Element = term()
Ordset = ordered_set()
Returns true if Element is an element of Ordset , otherwise false .
add_element(Element, Ordset1) > Ordset2
Types Element = term()
Ordset1 = Ordset2 = ordered_set()
Returns a new ordered set formed from Ordset1 with Element inserted.
del_element(Element, Ordset1) > Ordset2
Types Element = term()
Ordset1 = Ordset2 = ordered_set()
Returns Ordset1 , but with Element removed.
union(Ordset1, Ordset2) > Ordset3
Types Ordset1 = Ordset2 = Ordset3 = ordered_set()
Returns the merged (union) set of Ordset1 and Ordset2 .
union(OrdsetList) > Ordset
Types OrdsetList = [ordered_set()]
Ordset = ordered_set()
Returns the merged (union) set of the list of sets.
intersection(Ordset1, Ordset2) > Ordset3
Types Ordset1 = Ordset2 = Ordset3 = ordered_set()
Returns the intersection of Ordset1 and Ordset2 .
intersection(OrdsetList) > Ordset
Types OrdsetList = [ordered_set()]
Ordset = ordered_set()
Returns the intersection of the nonempty list of sets.
is_disjoint(Ordset1, Ordset2) > bool()
Types Ordset1 = Ordset2 = ordered_set()
Returns true if Ordset1 and Ordset2 are disjoint (have no elements in common), and
false otherwise.
subtract(Ordset1, Ordset2) > Ordset3
Types Ordset1 = Ordset2 = Ordset3 = ordered_set()
Returns only the elements of Ordset1 which are not also elements of Ordset2 .
is_subset(Ordset1, Ordset2) > bool()
Types Ordset1 = Ordset2 = ordered_set()
Returns true when every element of Ordset 1 is also a member of Ordset2 , otherwise
false .
fold(Function, Acc0, Ordset) > Acc1
Types Function = fun (E, AccIn) > AccOut
Acc0 = Acc1 = AccIn = AccOut = term()
Ordset = ordered_set()
Fold Function over every element in Ordset returning the final value of the accumu
lator.
filter(Pred, Ordset1) > Set2
Types Pred = fun (E) > bool()
Set1 = Set2 = ordered_set()
Filter elements in Set1 with boolean function Fun .
SEE ALSO
gb_sets(3erl) , sets(3erl)
Ericsson AB stdlib 1.17.3 ordsets(3erl) 
