sets(3erl)

1sets(3)                    Erlang Module Definition                    sets(3)
2
3
4

NAME

6       sets - Functions for set manipulation.
7

DESCRIPTION

9       Sets are collections of elements with no duplicate elements. The repre‐
10       sentation of a set is undefined.
11
12       This module provides the same interface as the  ordsets(3)  module  but
13       with  an  undefined  representation.  One difference is that while this
14       module considers two elements as different if they do not match  (=:=),
15       ordsets  considers two elements as different if and only if they do not
16       compare equal (==).
17
18       Erlang/OTP 24.0 introduced a new internal representation for sets which
19       is more performant. Developers can use this new representation by pass‐
20       ing  the  {version,  2}  flag  to  new/1  and  from_list/2,   such   as
21       sets:new([{version,  2}]).  This new representation will become the de‐
22       fault in future Erlang/OTP versions. Functions that work on  two  sets,
23       such as union/2 and similar, will work with sets of different versions.
24       In such cases, there is no guarantee about the version of the  returned
25       set.  Explicit  conversion  from  the old version to the new one can be
26       done with sets:from_list(sets:to_list(Old), [{version,2}]).
27

DATA TYPES

29       set(Element)
30
31              As returned by new/0.
32
33       set() = set(term())
34

EXPORTS

36       add_element(Element, Set1) -> Set2
37
38              Types:
39
40                 Set1 = Set2 = set(Element)
41
42              Returns a new set formed from Set1 with Element inserted.
43
44       del_element(Element, Set1) -> Set2
45
46              Types:
47
48                 Set1 = Set2 = set(Element)
49
50              Returns Set1, but with Element removed.
51
52       filter(Pred, Set1) -> Set2
53
54              Types:
55
56                 Pred = fun((Element) -> boolean())
57                 Set1 = Set2 = set(Element)
58
59              Filters elements in Set1 with boolean function Pred.
60
61       fold(Function, Acc0, Set) -> Acc1
62
63              Types:
64
65                 Function = fun((Element, AccIn) -> AccOut)
66                 Set = set(Element)
67                 Acc0 = Acc1 = AccIn = AccOut = Acc
68
69              Folds Function over every element in Set and returns  the  final
70              value of the accumulator. The evaluation order is undefined.
71
72       from_list(List) -> Set
73
74              Types:
75
76                 List = [Element]
77                 Set = set(Element)
78
79              Returns a set of the elements in List.
80
81       from_list(List, Opts :: [{version, 1..2}]) -> Set
82
83              Types:
84
85                 List = [Element]
86                 Set = set(Element)
87
88              Returns a set of the elements in List at the given version.
89
90       intersection(SetList) -> Set
91
92              Types:
93
94                 SetList = [set(Element), ...]
95                 Set = set(Element)
96
97              Returns the intersection of the non-empty list of sets.
98
99       intersection(Set1, Set2) -> Set3
100
101              Types:
102
103                 Set1 = Set2 = Set3 = set(Element)
104
105              Returns the intersection of Set1 and Set2.
106
107       is_disjoint(Set1, Set2) -> boolean()
108
109              Types:
110
111                 Set1 = Set2 = set(Element)
112
113              Returns  true if Set1 and Set2 are disjoint (have no elements in
114              common), otherwise false.
115
116       is_element(Element, Set) -> boolean()
117
118              Types:
119
120                 Set = set(Element)
121
122              Returns true if Element is an element of Set, otherwise false.
123
124       is_empty(Set) -> boolean()
125
126              Types:
127
128                 Set = set()
129
130              Returns true if Set is an empty set, otherwise false.
131
132       is_set(Set) -> boolean()
133
134              Types:
135
136                 Set = term()
137
138              Returns true if Set is a set of elements, otherwise false.
139
140       is_subset(Set1, Set2) -> boolean()
141
142              Types:
143
144                 Set1 = Set2 = set(Element)
145
146              Returns true when every element of Set1  is  also  a  member  of
147              Set2, otherwise false.
148
149       new() -> set()
150
151              Returns a new empty set.
152
153       new(Opts :: [{version, 1..2}]) -> set()
154
155              Returns a new empty set at the given version.
156
157       size(Set) -> integer() >= 0
158
159              Types:
160
161                 Set = set()
162
163              Returns the number of elements in Set.
164
165       subtract(Set1, Set2) -> Set3
166
167              Types:
168
169                 Set1 = Set2 = Set3 = set(Element)
170
171              Returns  only the elements of Set1 that are not also elements of
172              Set2.
173
174       to_list(Set) -> List
175
176              Types:
177
178                 Set = set(Element)
179                 List = [Element]
180
181              Returns the elements of Set as a list. The order of the returned
182              elements is undefined.
183
184       union(SetList) -> Set
185
186              Types:
187
188                 SetList = [set(Element)]
189                 Set = set(Element)
190
191              Returns the merged (union) set of the list of sets.
192
193       union(Set1, Set2) -> Set3
194
195              Types:
196
197                 Set1 = Set2 = Set3 = set(Element)
198
199              Returns the merged (union) set of Set1 and Set2.
200

NAME

DESCRIPTION

DATA TYPES

EXPORTS

SEE ALSO