1ordsets(3)                 Erlang Module Definition                 ordsets(3)
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NAME

6       ordsets - Functions for manipulating sets as ordered lists.
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DESCRIPTION

10       Sets  are collections of elements with no duplicate elements. An ordset
11       is a representation of a set, where an ordered list is  used  to  store
12       the  elements  of  the  set.  An ordered list is more efficient than an
13       unordered list. Elements are  ordered  according  to  the  Erlang  term
14       order.
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16       This  module provides the same interface as the sets(3) module but with
17       a defined representation. One difference is that while  sets  considers
18       two  elements as different if they do not match (=:=), this module con‐
19       siders two elements as different if and only if  they  do  not  compare
20       equal (==).
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DATA TYPES

23       ordset(T) = [T]
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25              As returned by new/0.
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EXPORTS

28       add_element(Element, Ordset1) -> Ordset2
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30              Types:
31
32                 Element = E
33                 Ordset1 = ordset(T)
34                 Ordset2 = ordset(T | E)
35
36              Returns  a  new  ordered  set  formed  from Ordset1 with Element
37              inserted.
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39       del_element(Element, Ordset1) -> Ordset2
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41              Types:
42
43                 Element = term()
44                 Ordset1 = Ordset2 = ordset(T)
45
46              Returns Ordset1, but with Element removed.
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48       filter(Pred, Ordset1) -> Ordset2
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50              Types:
51
52                 Pred = fun((Element :: T) -> boolean())
53                 Ordset1 = Ordset2 = ordset(T)
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55              Filters elements in Ordset1 with boolean function Pred.
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57       fold(Function, Acc0, Ordset) -> Acc1
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59              Types:
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61                 Function =
62                     fun((Element :: T, AccIn :: term()) -> AccOut :: term())
63                 Ordset = ordset(T)
64                 Acc0 = Acc1 = term()
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66              Folds Function over every element  in  Ordset  and  returns  the
67              final value of the accumulator.
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69       from_list(List) -> Ordset
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71              Types:
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73                 List = [T]
74                 Ordset = ordset(T)
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76              Returns an ordered set of the elements in List.
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78       intersection(OrdsetList) -> Ordset
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80              Types:
81
82                 OrdsetList = [ordset(term()), ...]
83                 Ordset = ordset(term())
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85              Returns the intersection of the non-empty list of sets.
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87       intersection(Ordset1, Ordset2) -> Ordset3
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89              Types:
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91                 Ordset1 = Ordset2 = Ordset3 = ordset(term())
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93              Returns the intersection of Ordset1 and Ordset2.
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95       is_disjoint(Ordset1, Ordset2) -> boolean()
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97              Types:
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99                 Ordset1 = Ordset2 = ordset(term())
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101              Returns  true  if Ordset1 and Ordset2 are disjoint (have no ele‐
102              ments in common), otherwise false.
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104       is_element(Element, Ordset) -> boolean()
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106              Types:
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108                 Element = term()
109                 Ordset = ordset(term())
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111              Returns true if Element  is  an  element  of  Ordset,  otherwise
112              false.
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114       is_set(Ordset) -> boolean()
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116              Types:
117
118                 Ordset = term()
119
120              Returns  true if Ordset is an ordered set of elements, otherwise
121              false.
122
123       is_subset(Ordset1, Ordset2) -> boolean()
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125              Types:
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127                 Ordset1 = Ordset2 = ordset(term())
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129              Returns true when every element of Ordset1 is also a  member  of
130              Ordset2, otherwise false.
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132       new() -> []
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134              Returns a new empty ordered set.
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136       size(Ordset) -> integer() >= 0
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138              Types:
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140                 Ordset = ordset(term())
141
142              Returns the number of elements in Ordset.
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144       subtract(Ordset1, Ordset2) -> Ordset3
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146              Types:
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148                 Ordset1 = Ordset2 = Ordset3 = ordset(term())
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150              Returns  only the elements of Ordset1 that are not also elements
151              of Ordset2.
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153       to_list(Ordset) -> List
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155              Types:
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157                 Ordset = ordset(T)
158                 List = [T]
159
160              Returns the elements of Ordset as a list.
161
162       union(OrdsetList) -> Ordset
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164              Types:
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166                 OrdsetList = [ordset(T)]
167                 Ordset = ordset(T)
168
169              Returns the merged (union) set of the list of sets.
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171       union(Ordset1, Ordset2) -> Ordset3
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173              Types:
174
175                 Ordset1 = ordset(T1)
176                 Ordset2 = ordset(T2)
177                 Ordset3 = ordset(T1 | T2)
178
179              Returns the merged (union) set of Ordset1 and Ordset2.
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SEE ALSO

182       gb_sets(3), sets(3)
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186Ericsson AB                     stdlib 3.4.5.1                      ordsets(3)