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 un‐
13       ordered list. Elements are ordered according to the Erlang term order.
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15       This module provides the same interface as the sets(3) module but  with
16       a  defined  representation. One difference is that while sets considers
17       two elements as different if they do not match (=:=), this module  con‐
18       siders  two  elements  as  different if and only if they do not compare
19       equal (==).
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DATA TYPES

22       ordset(T) = [T]
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24              As returned by new/0.
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EXPORTS

27       add_element(Element, Ordset1) -> Ordset2
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29              Types:
30
31                 Element = E
32                 Ordset1 = ordset(T)
33                 Ordset2 = ordset(T | E)
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35              Returns a new ordered set formed from Ordset1 with  Element  in‐
36              serted.
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38       del_element(Element, Ordset1) -> Ordset2
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40              Types:
41
42                 Element = term()
43                 Ordset1 = Ordset2 = ordset(T)
44
45              Returns Ordset1, but with Element removed.
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47       filter(Pred, Ordset1) -> Ordset2
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49              Types:
50
51                 Pred = fun((Element :: T) -> boolean())
52                 Ordset1 = Ordset2 = ordset(T)
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54              Filters elements in Ordset1 with boolean function Pred.
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56       fold(Function, Acc0, Ordset) -> Acc1
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58              Types:
59
60                 Function =
61                     fun((Element :: T, AccIn :: term()) -> AccOut :: term())
62                 Ordset = ordset(T)
63                 Acc0 = Acc1 = term()
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65              Folds  Function over every element in Ordset and returns the fi‐
66              nal value of the accumulator.
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68       from_list(List) -> Ordset
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70              Types:
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72                 List = [T]
73                 Ordset = ordset(T)
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75              Returns an ordered set of the elements in List.
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77       intersection(OrdsetList) -> Ordset
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79              Types:
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81                 OrdsetList = [ordset(term()), ...]
82                 Ordset = ordset(term())
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84              Returns the intersection of the non-empty list of sets.
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86       intersection(Ordset1, Ordset2) -> Ordset3
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88              Types:
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90                 Ordset1 = Ordset2 = Ordset3 = ordset(term())
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92              Returns the intersection of Ordset1 and Ordset2.
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94       is_disjoint(Ordset1, Ordset2) -> boolean()
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96              Types:
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98                 Ordset1 = Ordset2 = ordset(term())
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100              Returns true if Ordset1 and Ordset2 are disjoint (have  no  ele‐
101              ments in common), otherwise false.
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103       is_element(Element, Ordset) -> boolean()
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105              Types:
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107                 Element = term()
108                 Ordset = ordset(term())
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110              Returns  true  if  Element  is  an  element of Ordset, otherwise
111              false.
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113       is_empty(Ordset) -> boolean()
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115              Types:
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117                 Ordset = ordset(term())
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119              Returns true if Ordset is an empty set, otherwise false.
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121       is_set(Ordset) -> boolean()
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123              Types:
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125                 Ordset = term()
126
127              Returns true if Ordset is an ordered set of elements,  otherwise
128              false. This function will return true for any ordered list, even
129              when not constructed by the functions in this module.
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131       is_subset(Ordset1, Ordset2) -> boolean()
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133              Types:
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135                 Ordset1 = Ordset2 = ordset(term())
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137              Returns true when every element of Ordset1 is also a  member  of
138              Ordset2, otherwise false.
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140       new() -> []
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142              Returns a new empty ordered set.
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144       size(Ordset) -> integer() >= 0
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146              Types:
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148                 Ordset = ordset(term())
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150              Returns the number of elements in Ordset.
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152       subtract(Ordset1, Ordset2) -> Ordset3
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154              Types:
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156                 Ordset1 = Ordset2 = Ordset3 = ordset(term())
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158              Returns  only the elements of Ordset1 that are not also elements
159              of Ordset2.
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161       to_list(Ordset) -> List
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163              Types:
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165                 Ordset = ordset(T)
166                 List = [T]
167
168              Returns the elements of Ordset as a list.
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170       union(OrdsetList) -> Ordset
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172              Types:
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174                 OrdsetList = [ordset(T)]
175                 Ordset = ordset(T)
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177              Returns the merged (union) set of the list of sets.
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179       union(Ordset1, Ordset2) -> Ordset3
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181              Types:
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183                 Ordset1 = ordset(T1)
184                 Ordset2 = ordset(T2)
185                 Ordset3 = ordset(T1 | T2)
186
187              Returns the merged (union) set of Ordset1 and Ordset2.
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SEE ALSO

190       gb_sets(3), sets(3)
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194Ericsson AB                       stdlib 4.2                        ordsets(3)