.TH sets 3 "stdlib  1.15.3" "Ericsson AB" "ERLANG MODULE DEFINITION"
.SH MODULE
sets \- Functions for Set Manipulation
.SH DESCRIPTION
.LP
Sets are collections of elements with no duplicate elements\&. The representation of a set is not defined\&.
.LP
This module provides exactly the same interface as the module \fIordsets\fR but with a defined representation\&. One difference is that while this module considers two elements as different if they do not match (\fI=:=\fR), \fIordsets\fR considers two elements as different if and only if they do not compare equal (\fI==\fR)\&.

.SH DATA TYPES

.nf
set()
  as returned by new/0
.fi
.SH EXPORTS
.LP
.B
new() -> Set
.br
.RS
.TP
Types
Set = set()
.br
.RE
.RS
.LP
Returns a new empty set\&.
.RE
.LP
.B
is_set(Set) -> bool()
.br
.RS
.TP
Types
Set = term()
.br
.RE
.RS
.LP
Returns \fItrue\fR if \fISet\fR is a set of elements, otherwise \fIfalse\fR\&.
.RE
.LP
.B
size(Set) -> int()
.br
.RS
.TP
Types
Set = term()
.br
.RE
.RS
.LP
Returns the number of elements in \fISet\fR\&.
.RE
.LP
.B
to_list(Set) -> List
.br
.RS
.TP
Types
Set = set()
.br
List = [term()]
.br
.RE
.RS
.LP
Returns the elements of \fISet\fR as a list\&.
.RE
.LP
.B
from_list(List) -> Set
.br
.RS
.TP
Types
List = [term()]
.br
Set = set()
.br
.RE
.RS
.LP
Returns an set of the elements in \fIList\fR\&.
.RE
.LP
.B
is_element(Element, Set) -> bool()
.br
.RS
.TP
Types
Element = term()
.br
Set = set()
.br
.RE
.RS
.LP
Returns \fItrue\fR if \fIElement\fR is an element of \fISet\fR, otherwise \fIfalse\fR\&.
.RE
.LP
.B
add_element(Element, Set1) -> Set2
.br
.RS
.TP
Types
Element = term()
.br
Set1 = Set2 = set()
.br
.RE
.RS
.LP
Returns a new set formed from \fISet1\fR with \fIElement\fR inserted\&.
.RE
.LP
.B
del_element(Element, Set1) -> Set2
.br
.RS
.TP
Types
Element = term()
.br
Set1 = Set2 = set()
.br
.RE
.RS
.LP
Returns \fISet1\fR, but with \fIElement\fR removed\&.
.RE
.LP
.B
union(Set1, Set2) -> Set3
.br
.RS
.TP
Types
Set1 = Set2 = Set3 = set()
.br
.RE
.RS
.LP
Returns the merged (union) set of \fISet1\fR and \fISet2\fR\&.
.RE
.LP
.B
union(SetList) -> Set
.br
.RS
.TP
Types
SetList = [set()]
.br
Set = set()
.br
.RE
.RS
.LP
Returns the merged (union) set of the list of sets\&.
.RE
.LP
.B
intersection(Set1, Set2) -> Set3
.br
.RS
.TP
Types
Set1 = Set2 = Set3 = set()
.br
.RE
.RS
.LP
Returns the intersection of \fISet1\fR and \fISet2\fR\&.
.RE
.LP
.B
intersection(SetList) -> Set
.br
.RS
.TP
Types
SetList = [set()]
.br
Set = set()
.br
.RE
.RS
.LP
Returns the intersection of the non-empty list of sets\&.
.RE
.LP
.B
subtract(Set1, Set2) -> Set3
.br
.RS
.TP
Types
Set1 = Set2 = Set3 = set()
.br
.RE
.RS
.LP
Returns only the elements of \fISet1\fR which are not also elements of \fISet2\fR\&.
.RE
.LP
.B
is_subset(Set1, Set2) -> bool()
.br
.RS
.TP
Types
Set1 = Set2 = set()
.br
.RE
.RS
.LP
Returns \fItrue\fR when every element of \fISet\fR1 is also a member of \fISet2\fR, otherwise \fIfalse\fR\&.
.RE
.LP
.B
fold(Function, Acc0, Set) -> Acc1
.br
.RS
.TP
Types
Function = fun (E, AccIn) -> AccOut
.br
Acc0 = Acc1 = AccIn = AccOut = term()
.br
Set = set()
.br
.RE
.RS
.LP
Fold \fIFunction\fR over every element in \fISet\fR returning the final value of the accumulator\&.
.RE
.LP
.B
filter(Pred, Set1) -> Set2
.br
.RS
.TP
Types
Pred = fun (E) -> bool()
.br
Set1 = Set2 = set()
.br
.RE
.RS
.LP
Filter elements in \fISet1\fR with boolean function \fIFun\fR\&.
.RE
.SH SEE ALSO
.LP
ordsets(3), gb_sets(3)