123456789_123456789_123456789_123456789_123456789_

Class: Set

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, ::Enumerable
Inherits: Object
Defined in: lib/set.rb

Overview

This library provides the Set class, which deals with a collection of unordered values with no duplicates. It is a hybrid of Array’s intuitive inter-operation facilities and Hash’s fast lookup.

The method #to_set is added to ::Enumerable for convenience.

Set implements a collection of unordered values with no duplicates. This is a hybrid of Array’s intuitive inter-operation facilities and Hash’s fast lookup.

Set is easy to use with ::Enumerable objects (implementing #each). Most of the initializer methods and binary operators accept generic ::Enumerable objects besides sets and arrays. An Enumerable object can be converted to Set using the #to_set method.

Set uses Hash as storage, so you must note the following points:

  • Equality of elements is determined according to Object#eql? and Object#hash. Use Set#compare_by_identity to make a set compare its elements by their identity.

  • Set assumes that the identity of each element does not change while it is stored. Modifying an element of a set will render the set to an unreliable state.

  • When a string is to be stored, a frozen copy of the string is stored instead unless the original string is already frozen.

Comparison

The comparison operators ‘<`, #>, #<=, and #>= are implemented as shorthand for the proper_,subset?,superset? methods. The #<=> operator reflects this order, or return nil for sets that both have distinct elements (`y` vs. {x, z} for example).

Example

“‘ruby require ’set’ s1 = Set[1, 2] #=> #<Set: 2> s2 = [1, 2].to_set #=> #<Set: 2> s1 == s2 #=> true s1.add(“foo”) #=> #<Set: 2, “foo”> s1.merge([2, 6]) #=> #<Set: 2, “foo”, 6> s1.subset?(s2) #=> false s2.subset?(s1) #=> true “‘

Contact

  • Akinori MUSHA <<knu@iDaemons.org>> (current maintainer)

Constant Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

::Enumerable - Included

#to_set

Makes a set from the enumerable object with given arguments.

Constructor Details

.new(enum = nil, &block) ⇒ Set

Creates a new set containing the elements of the given enumerable object.

If a block is given, the elements of enum are preprocessed by the given block.

Set.new([1, 2])                       #=> #<Set: {1, 2}>
Set.new([1, 2, 1])                    #=> #<Set: {1, 2}>
Set.new([1, 'c', :s])                 #=> #<Set: {1, "c", :s}>
Set.new(1..5)                         #=> #<Set: {1, 2, 3, 4, 5}>
Set.new([1, 2, 3]) { |x| x * x }      #=> #<Set: {1, 4, 9}>
[ GitHub ] 

  


# File 'lib/set.rb', line 88



def initialize(enum = nil, &block) # :yields: o
  @hash ||= Hash.new(false)

  enum.nil? and return

  if block
    do_with_enum(enum) { |o| add(block[o]) }
  else
    merge(enum)
  end
end


  







Class Method Details



  

    .[](*ary)  
  



  

    

Creates a new set containing the given objects.



Set[1, 2]                   # => #<Set: {1, 2}>
Set[1, 2, 1]                # => #<Set: {1, 2}>
Set[1, 'c', :s]             # => #<Set: {1, "c", :s}>


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 73



def self.[](*ary)
  new(ary)
end


  







Instance Attribute Details



  

    #compare_by_identity   (readonly)
  



  

    

Makes the set compare its elements by their identity and returns self.  This method may not be supported by all subclasses of Set.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 102



def compare_by_identity
  if @hash.respond_to?(:compare_by_identity)
    @hash.compare_by_identity
    self
  else
    raise NotImplementedError, "#{self.class.name}\##{__method__} is not implemented"
  end
end


  








  

    #compare_by_identity?  ⇒ Boolean  (readonly)
  



  

    

Returns true if the set will compare its elements by their identity.  Also see #compare_by_identity.


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 113



def compare_by_identity?
  @hash.respond_to?(:compare_by_identity?) && @hash.compare_by_identity?
end


  








  

    #empty?  ⇒ Boolean  (readonly)
  



  

    

Returns true if the set contains no elements.


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 160



def empty?
  @hash.empty?
end


  







Instance Method Details



  

    #&(enum)  
    Also known as: #intersection
  



  

    

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



Set[1, 3, 5] & Set[3, 2, 1]             #=> #<Set: {3, 1}>
Set['a', 'b', 'z'] & ['a', 'b', 'c']    #=> #<Set: {"a", "b"}>


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 481



def &(enum)
  n = self.class.new
  if enum.is_a?(Set)
    if enum.size > size
      each { |o| n.add(o) if enum.include?(o) }
    else
      enum.each { |o| n.add(o) if include?(o) }
    end
  else
    do_with_enum(enum) { |o| n.add(o) if include?(o) }
  end
  n
end


  








  

    #+(enum)  
  



  

    

Alias for #|.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 463



alias + |


  








  

    #-(enum)  
    Also known as: #difference
  



  

    

Returns a new set built by duplicating the set, removing every element that appears in the given enumerable object.



Set[1, 3, 5] - Set[1, 5]                #=> #<Set: {3}>
Set['a', 'b', 'z'] - ['a', 'c']         #=> #<Set: {"b", "z"}>


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 471



def -(enum)
  dup.subtract(enum)
end


  








  

    #<(set)  
  



  

    

Alias for #proper_subset?.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 301



alias < proper_subset?


  








  

    #<<(o)  
  



  

    

Alias for #add.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 358



alias << add


  








  

    #<=(set)  
  



  

    

Alias for #subset?.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 288



alias <= subset?


  








  

    #<=>(set)  
  



  

    

Returns 0 if the set are equal, -1 / +1 if the set is a proper subset / superset of the given set, or nil if they both have unique elements.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 306



def <=>(set)
  return unless set.is_a?(Set)

  case size <=> set.size
  when -1 then -1 if proper_subset?(set)
  when +1 then +1 if proper_superset?(set)
  else 0 if self.==(set)
  end
end


  








  

    #==(other)  
  



  

    

Returns true if two sets are equal.  The equality of each couple of elements is defined according to Object#eql?.



Set[1, 2] == Set[2, 1]                       #=> true
Set[1, 3, 5] == Set[1, 5]                    #=> false
Set['a', 'b', 'c'] == Set['a', 'c', 'b']     #=> true
Set['a', 'b', 'c'] == ['a', 'c', 'b']        #=> false


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 515



def ==(other)
  if self.equal?(other)
    true
  elsif other.instance_of?(self.class)
    @hash == other.instance_variable_get(:@hash)
  elsif other.is_a?(Set) && self.size == other.size
    other.all? { |o| @hash.include?(o) }
  else
    false
  end
end


  








  

    #===(o)  
  



  

    

Alias for #include?.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 569



alias === include?


  








  

    #>(set)  
  



  

    

Alias for #proper_superset?.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 275



alias > proper_superset?


  








  

    #>=(set)  
  



  

    

Alias for #superset?.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 262



alias >= superset?


  








  

    #^(enum)  
  



  

    

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



Set[1, 2] ^ Set[2, 3]                   #=> #<Set: {3, 1}>
Set[1, 'b', 'c'] ^ ['b', 'd']           #=> #<Set: {"d", 1, "c"}>


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 502



def ^(enum)
  n = Set.new(enum)
  each { |o| n.add(o) unless n.delete?(o) }
  n
end


  








  

    #add(o)  
    Also known as: #<<
  



  

    

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



Set[1, 2].add(3)                    #=> #<Set: {1, 2, 3}>
Set[1, 2].add([3, 4])               #=> #<Set: {1, 2, [3, 4]}>
Set[1, 2].add(2)                    #=> #<Set: {1, 2}>


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 354



def add(o)
  @hash[o] = true
  self
end


  








  

    #add?(o)  ⇒ Boolean 
  



  

    

Adds the given object to the set and returns self.  If the object is already in the set, returns nil.



Set[1, 2].add?(3)                    #=> #<Set: {1, 2, 3}>
Set[1, 2].add?([3, 4])               #=> #<Set: {1, 2, [3, 4]}>
Set[1, 2].add?(2)                    #=> nil


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 366



def add?(o)
  add(o) unless include?(o)
end


  








  

    #classify  
  



  

    

Classifies the set by the return value of the given block and returns a hash of => set of elements pairs.  The block is called once for each element of the set, passing the element as parameter.



require 'set'
files = Set.new(Dir.glob("*.rb"))
hash = files.classify { |f| File.mtime(f).year }
hash       #=> {2000=>#<Set: {"a.rb", "b.rb"}>,
           #    2001=>#<Set: {"c.rb", "d.rb", "e.rb"}>,
           #    2002=>#<Set: {"f.rb"}>}



Returns an enumerator if no block is given.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 584



def classify # :yields: o
  block_given? or return enum_for(__method__) { size }

  h = {}

  each { |i|
    (h[yield(i)] ||= self.class.new).add(i)
  }

  h
end


  








  

    #clear  
  



  

    

Removes all elements and returns self.



set = Set[1, 'c', :s]             #=> #<Set: {1, "c", :s}>
set.clear                         #=> #<Set: {}>
set                               #=> #<Set: {}>


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 169



def clear
  @hash.clear
  self
end


  








  

    #collect!  
    Also known as: #map!
  



  

    

Replaces the elements with ones returned by collect(). Returns an enumerator if no block is given.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 407



def collect!
  block_given? or return enum_for(__method__) { size }
  set = self.class.new
  each { |o| set << yield(o) }
  replace(set)
end


  








  

    #delete(o)  
  



  

    

Deletes the given object from the set and returns self.  Use #subtract to delete many items at once.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 372



def delete(o)
  @hash.delete(o)
  self
end


  








  

    #delete?(o)  ⇒ Boolean 
  



  

    

Deletes the given object from the set and returns self.  If the object is not in the set, returns nil.


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 379



def delete?(o)
  delete(o) if include?(o)
end


  








  

    #delete_if  
  



  

    

Deletes every element of the set for which block evaluates to true, and returns self. Returns an enumerator if no block is given.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 386



def delete_if
  block_given? or return enum_for(__method__) { size }
  # @hash.delete_if should be faster, but using it breaks the order
  # of enumeration in subclasses.
  select { |o| yield o }.each { |o| @hash.delete(o) }
  self
end


  








  

    #difference(enum)  
  



  

    

Alias for #-.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 474



alias difference -


  








  

    #disjoint?(set)  ⇒ Boolean 
  



  

    

Returns true if the set and the given set have no element in common.  This method is the opposite of #intersect?.



Set[1, 2, 3].disjoint? Set[3, 4]   #=> false
Set[1, 2, 3].disjoint? Set[4, 5]   #=> true


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 335



def disjoint?(set)
  !intersect?(set)
end


  








  

    #divide(&func)  
  



  

    

Divides the set into a set of subsets according to the commonality defined by the given block.



If the arity of the block is 2, elements o1 and o2 are in common if block.call(o1, o2) is true.  Otherwise, elements o1 and o2 are in common if block.call(o1) == block.call(o2).



require 'set'
numbers = Set[1, 3, 4, 6, 9, 10, 11]
set = numbers.divide { |i,j| (i - j).abs == 1 }
set        #=> #<Set: {#<Set: {1}>,
           #           #<Set: {11, 9, 10}>,
           #           #<Set: {3, 4}>,
           #           #<Set: {6}>}>



Returns an enumerator if no block is given.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 612



def divide(&func)
  func or return enum_for(__method__) { size }

  if func.arity == 2
    require 'tsort'

    class << dig = {}         # :nodoc:
      include TSort

      alias tsort_each_node each_key
      def tsort_each_child(node, &block)
        fetch(node).each(&block)
      end
    end

    each { |u|
      dig[u] = a = []
      each{ |v| func.call(u, v) and a << v }
    }

    set = Set.new()
    dig.each_strongly_connected_component { |css|
      set.add(self.class.new(css))
    }
    set
  else
    Set.new(classify(&func).values)
  end
end


  








  

    #do_with_enum(enum, &block)   (private)
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/set.rb', line 117



def do_with_enum(enum, &block) # :nodoc:
  if enum.respond_to?(:each_entry)
    enum.each_entry(&block) if block
  elsif enum.respond_to?(:each)
    enum.each(&block) if block
  else
    raise ArgumentError, "value must be enumerable"
  end
end


  








  

    #each(&block)  
  



  

    

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


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 342



def each(&block)
  block or return enum_for(__method__) { size }
  @hash.each_key(&block)
  self
end


  








  

    #eql?(o)  ⇒ Boolean 
  

  

    This method is for internal use only.
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 531



def eql?(o)   # :nodoc:
  return false unless o.is_a?(Set)
  @hash.eql?(o.instance_variable_get(:@hash))
end


  








  

    #filter!(&block)  
  



  

    

Alias for #select!.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 434



alias filter! select!


  








  

    #flatten  
  



  

    

Returns a new set that is a copy of the set, flattening each containing set recursively.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 230



def flatten
  self.class.new.flatten_merge(self)
end


  








  

    #flatten!  
  



  

    

Equivalent to #flatten, but replaces the receiver with the result in place.  Returns nil if no modifications were made.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 236



def flatten!
  replace(flatten()) if any? { |e| e.is_a?(Set) }
end


  








  

    #flatten_merge(set, seen = Set.new)   (protected)
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/set.rb', line 209



def flatten_merge(set, seen = Set.new) # :nodoc:
  set.each { |e|
    if e.is_a?(Set)
      if seen.include?(e_id = e.object_id)
        raise ArgumentError, "tried to flatten recursive Set"
      end

      seen.add(e_id)
      flatten_merge(e, seen)
      seen.delete(e_id)
    else
      add(e)
    end
  }

  self
end


  








  

    #freeze  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/set.rb', line 148



def freeze    # :nodoc:
  @hash.freeze
  super
end


  








  

    #hash  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/set.rb', line 527



def hash      # :nodoc:
  @hash.hash
end


  








  

    #include?(o)  ⇒ Boolean 
    Also known as: #member?, #===
  



  

    

Returns true if the set contains the given object.



Note that include? and #member? do not test member equality using #== as do other Enumerables.



See also Enumerable#include?


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 246



def include?(o)
  @hash[o]
end


  








  

    #initialize_clone(orig)  
  



  

    

Clone internal hash.



See additional method definition at line 136.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 142



def initialize_clone(orig, **options)
  super
  @hash = orig.instance_variable_get(:@hash).clone(**options)
end


  








  

    #initialize_dup(orig)  
  



  

    

Dup internal hash.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 129



def initialize_dup(orig)
  super
  @hash = orig.instance_variable_get(:@hash).dup
end


  








  

    #inspect  
    Also known as: #to_s
  



  

    

Returns a string containing a human-readable representation of the set (“#<Set: element2, …>”).


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 652



def inspect
  ids = (Thread.current[InspectKey] ||= [])

  if ids.include?(object_id)
    return sprintf('#<%s: {...}>', self.class.name)
  end

  ids << object_id
  begin
    return sprintf('#<%s: {%s}>', self.class, to_a.inspect[1..-2])
  ensure
    ids.pop
  end
end


  








  

    #intersect?(set)  ⇒ Boolean 
  



  

    

Returns true if the set and the given set have at least one element in common.



Set[1, 2, 3].intersect? Set[4, 5]   #=> false
Set[1, 2, 3].intersect? Set[3, 4]   #=> true


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 321



def intersect?(set)
  set.is_a?(Set) or raise ArgumentError, "value must be a set"
  if size < set.size
    any? { |o| set.include?(o) }
  else
    set.any? { |o| include?(o) }
  end
end


  








  

    #intersection(enum)  
  



  

    

Alias for #&.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 494



alias intersection &


  








  

    #join(separator = nil)  
  



  

    

Returns a string created by converting each element of the set to a string See also: Array#join


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 644



def join(separator=nil)
  to_a.join(separator)
end


  








  

    #keep_if  
  



  

    

Deletes every element of the set for which block evaluates to false, and returns self. Returns an enumerator if no block is given.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 397



def keep_if
  block_given? or return enum_for(__method__) { size }
  # @hash.keep_if should be faster, but using it breaks the order of
  # enumeration in subclasses.
  reject { |o| yield o }.each { |o| @hash.delete(o) }
  self
end


  








  

    #length  
  



  

    

Alias for #size.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 157



alias length size


  








  

    #map!  
  



  

    

Alias for #collect!.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 413



alias map! collect!


  








  

    #member?(o)  
  



  

    

Alias for #include?.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 249



alias member? include?


  








  

    #merge(enum)  
  



  

    

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


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 438



def merge(enum)
  if enum.instance_of?(self.class)
    @hash.update(enum.instance_variable_get(:@hash))
  else
    do_with_enum(enum) { |o| add(o) }
  end

  self
end


  








  

    #pretty_print(pp)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/set.rb', line 669



def pretty_print(pp)  # :nodoc:
  pp.text sprintf('#<%s: {', self.class.name)
  pp.nest(1) {
    pp.seplist(self) { |o|
      pp.pp o
    }
  }
  pp.text "}>"
end


  








  

    #pretty_print_cycle(pp)  
  

  

    This method is for internal use only.
  

  [ GitHub ]


  

  


# File 'lib/set.rb', line 679



def pretty_print_cycle(pp)    # :nodoc:
  pp.text sprintf('#<%s: {%s}>', self.class.name, empty? ? '' : '...')
end


  








  

    #proper_subset?(set)  ⇒ Boolean 
    Also known as: #<
  



  

    

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


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 291



def proper_subset?(set)
  case
  when set.instance_of?(self.class) && @hash.respond_to?(:<)
    @hash < set.instance_variable_get(:@hash)
  when set.is_a?(Set)
    size < set.size && all? { |o| set.include?(o) }
  else
    raise ArgumentError, "value must be a set"
  end
end


  








  

    #proper_superset?(set)  ⇒ Boolean 
    Also known as: #>
  



  

    

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


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 265



def proper_superset?(set)
  case
  when set.instance_of?(self.class) && @hash.respond_to?(:>)
    @hash > set.instance_variable_get(:@hash)
  when set.is_a?(Set)
    size > set.size && set.all? { |o| include?(o) }
  else
    raise ArgumentError, "value must be a set"
  end
end


  








  

    #reject!(&block)  
  



  

    

Equivalent to #delete_if, but returns nil if no changes were made. Returns an enumerator if no block is given.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 417



def reject!(&block)
  block or return enum_for(__method__) { size }
  n = size
  delete_if(&block)
  self if size != n
end


  








  

    #replace(enum)  
  



  

    

Replaces the contents of the set with the contents of the given enumerable object and returns self.



set = Set[1, 'c', :s]             #=> #<Set: {1, "c", :s}>
set.replace([1, 2])               #=> #<Set: {1, 2}>
set                               #=> #<Set: {1, 2}>


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 180



def replace(enum)
  if enum.instance_of?(self.class)
    @hash.replace(enum.instance_variable_get(:@hash))
    self
  else
    do_with_enum(enum)  # make sure enum is enumerable before calling clear
    clear
    merge(enum)
  end
end


  








  

    #reset  
  



  

    

Resets the internal state after modification to existing elements and returns self.



Elements will be reindexed and deduplicated.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 540



def reset
  if @hash.respond_to?(:rehash)
    @hash.rehash # This should perform frozenness check.
  else
    raise FrozenError, "can't modify frozen #{self.class.name}" if frozen?
  end
  self
end


  








  

    #select!(&block)  
    Also known as: #filter!
  



  

    

Equivalent to #keep_if, but returns nil if no changes were made. Returns an enumerator if no block is given.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 426



def select!(&block)
  block or return enum_for(__method__) { size }
  n = size
  keep_if(&block)
  self if size != n
end


  








  

    #size  
    Also known as: #length
  



  

    

Returns the number of elements.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 154



def size
  @hash.size
end


  








  

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



  

    

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


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 278



def subset?(set)
  case
  when set.instance_of?(self.class) && @hash.respond_to?(:<=)
    @hash <= set.instance_variable_get(:@hash)
  when set.is_a?(Set)
    size <= set.size && all? { |o| set.include?(o) }
  else
    raise ArgumentError, "value must be a set"
  end
end


  








  

    #subtract(enum)  
  



  

    

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


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 450



def subtract(enum)
  do_with_enum(enum) { |o| delete(o) }
  self
end


  








  

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



  

    

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


  





  


  [ GitHub ]


  

  


# File 'lib/set.rb', line 252



def superset?(set)
  case
  when set.instance_of?(self.class) && @hash.respond_to?(:>=)
    @hash >= set.instance_variable_get(:@hash)
  when set.is_a?(Set)
    size >= set.size && set.all? { |o| include?(o) }
  else
    raise ArgumentError, "value must be a set"
  end
end


  








  

    #to_a  
  



  

    

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



Set[1, 2].to_a                    #=> [1, 2]
Set[1, 'c', :s].to_a              #=> [1, "c", :s]


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 195



def to_a
  @hash.keys
end


  








  

    #to_s  
  



  

    

Alias for #inspect.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 667



alias to_s inspect


  








  

    #to_set(klass = Set, *args, &block)  
  



  

    

Returns self if no arguments are given.  Otherwise, converts the set to another with klass.new(self, *args, &block).



In subclasses, returns klass.new(self, *args, &block) unless overridden.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 204



def to_set(klass = Set, *args, &block)
  return self if instance_of?(Set) && klass == Set && block.nil? && args.empty?
  klass.new(self, *args, &block)
end


  








  

    #union(enum)  
  



  

    

Alias for #|.


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 464



alias union |


  








  

    #|(enum)  
    Also known as: #+, #union
  



  

    

Returns a new set built by merging the set and the elements of the given enumerable object.



Set[1, 2, 3] | Set[2, 4, 5]         #=> #<Set: {1, 2, 3, 4, 5}>
Set[1, 5, 'z'] | (1..6)             #=> #<Set: {1, 5, "z", 2, 3, 4, 6}>


  



  [ GitHub ]


  

  


# File 'lib/set.rb', line 460



def |(enum)
  dup.merge(enum)
end