Class: Multiset

Inherits:
Set
  • Object
show all
Defined in:
lib/rack/mount/vendor/multimap/multiset.rb

Overview

Multiset implements a collection of unordered values and allows duplicate values.

Instance Method Summary collapse

Constructor Details

#initialize(*args, &block) ⇒ Multiset

:nodoc:



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 6

def initialize(*args, &block) #:nodoc:
  @hash = Hash.new(0)
  super
end

Instance Method Details

#&(enum) ⇒ Object Also known as: intersection

Returns a new set containing elements common to the set and the given enumerable object.



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 120

def &(enum)
  s = dup
  n = self.class.new
  enum.each { |o|
    if s.include?(o)
      s.delete(o, 1)
      n.add(o)
    end
  }
  n
end

#^(enum) ⇒ Object

Returns a new set containing elements exclusive between the set and the given enumerable object. (set ^ enum) is equivalent to ((set | enum) - (set & enum)).



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 136

def ^(enum)
  n = self.class.new(enum)
  each { |o| n.include?(o) ? n.delete(o, 1) : n.add(o) }
  n
end

#add(o) ⇒ Object Also known as: <<

Adds the given object to the set and returns self. Use merge to add many elements at once.



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 71

def add(o)
  @hash[o] ||= 0
  @hash[o] += 1
  self
end

#cardinality ⇒ Object Also known as: size, length

Returns the total number of elements in a multiset, including repeated memberships



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 18

def cardinality
  @hash.inject(0) { |s, (e, m)| s += m }
end

#delete(o, n = nil) ⇒ Object

Deletes all the identical object from the set and returns self. If n is given, it will remove that amount of identical objects from the set. Use subtract to delete many different items at once.



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 84

def delete(o, n = nil)
  if n
    @hash[o] ||= 0
    @hash[o] -= n if @hash[o] > 0
    @hash.delete(o) if @hash[o] == 0
  else
    @hash.delete(o)
  end
  self
end

#delete_if ⇒ Object

Deletes every element of the set for which block evaluates to true, and returns self.



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 99

def delete_if
  each { |o| delete(o) if yield(o) }
  self
end

#each ⇒ Object

Calls the given block once for each element in the set, passing the element as parameter. Returns an enumerator if no block is given.



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 60

def each
  @hash.each_pair do |key, multiplicity|
    multiplicity.times do
      yield(key)
    end
  end
  self
end

#eql?(set) ⇒ Boolean Also known as: ==

Returns true if two sets are equal. Two multisets are equal if they have the same cardinalities and each element has the same multiplicity in both sets. The equality of each element inside the multiset is defined according to Object#eql?.

Returns:

  • (Boolean) 


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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 146

def eql?(set)
  return true if equal?(set)
  set = self.class.new(set) unless set.is_a?(self.class)
  return false unless cardinality == set.cardinality
  superset?(set) && subset?(set)
end

#merge(enum) ⇒ Object

Merges the elements of the given enumerable object to the set and returns self.



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 106

def merge(enum)
  enum.each { |o| add(o) }
  self
end

#multiplicity(e) ⇒ Object

Returns the number of times an element belongs to the multiset.



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 12

def multiplicity(e)
  @hash[e]
end

#proper_subset?(set) ⇒ Boolean

Returns true if the set is a proper subset of the given set.

Returns:

  • (Boolean) 


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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 51

def proper_subset?(set)
  set.is_a?(self.class) or raise ArgumentError, "value must be a set"
  return false if set.cardinality <= cardinality
  all? { |o| multiplicity(o) <= set.multiplicity(o) }
end

#proper_superset?(set) ⇒ Boolean

Returns true if the set is a proper superset of the given set.

Returns:

  • (Boolean) 


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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 37

def proper_superset?(set)
  set.is_a?(self.class) or raise ArgumentError, "value must be a set"
  return false if cardinality <= set.cardinality
  set.all? { |o| set.multiplicity(o) <= multiplicity(o) }
end

#subset?(set) ⇒ Boolean

Returns true if the set is a subset of the given set.

Returns:

  • (Boolean) 


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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 44

def subset?(set)
  set.is_a?(self.class) or raise ArgumentError, "value must be a set"
  return false if set.cardinality < cardinality
  all? { |o| multiplicity(o) <= set.multiplicity(o) }
end

#subtract(enum) ⇒ Object

Deletes every element that appears in the given enumerable object and returns self.



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 113

def subtract(enum)
  enum.each { |o| delete(o, 1) }
  self
end

#superset?(set) ⇒ Boolean

Returns true if the set is a superset of the given set.

Returns:

  • (Boolean) 


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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 30

def superset?(set)
  set.is_a?(self.class) or raise ArgumentError, "value must be a set"
  return false if cardinality < set.cardinality
  set.all? { |o| set.multiplicity(o) <= multiplicity(o) }
end

#to_a ⇒ Object

Converts the set to an array. The order of elements is uncertain.



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# File 'lib/rack/mount/vendor/multimap/multiset.rb', line 25

def to_a
  inject([]) { |ary, (key, _)| ary << key }
end