Class: Set

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/set.rb

Overview

This library provides the Set class, which implements 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 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. `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)

## What’s Here

First, what's elsewhere. \Class \Set:

In particular, class Set does not have many methods of its own for fetching or for iterating. Instead, it relies on those in Enumerable.

Here, class Set provides methods that are useful for:

  • [Creating a Set](#class-Set-label-Methods+for+Creating+a+Set)

  • [Set Operations](#class-Set-label-Methods+for+Set+Operations)

  • [Comparing](#class-Set-label-Methods+for+Comparing)

  • [Querying](#class-Set-label-Methods+for+Querying)

  • [Assigning](#class-Set-label-Methods+for+Assigning)

  • [Deleting](#class-Set-label-Methods+for+Deleting)

  • [Converting](#class-Set-label-Methods+for+Converting)

  • [Iterating](#class-Set-label-Methods+for+Iterating)

  • [And more.…](#class-Set-label-Other+Methods)

### Methods for Creating a Set

  • ::[]: Returns a new set containing the given objects.

  • ::new: Returns a new set containing either the given objects (if no block given) or the return values from the called block (if a block given).

### Methods for Set Operations

  • [|](#method-i-7C) (aliased as #union and #+): Returns a new set containing all elements from self and all elements from a given enumerable (no duplicates).

  • [&](#method-i-26) (aliased as #intersection): Returns a new set containing all elements common to self and a given enumerable.

  • [-](#method-i-2D) (aliased as #difference): Returns a copy of self with all elements in a given enumerable removed.

  • [^](#method-i-5E): Returns a new set containing all elements from self and a given enumerable except those common to both.

### Methods for Comparing

  • [<=>](#method-i-3C-3D-3E): Returns -1, 0, or 1 as self is less than, equal to, or greater than a given object.

  • [==](#method-i-3D-3D): Returns whether self and a given enumerable are equal, as determined by Object#eql?.

  • #compare_by_identity?: Returns whether the set considers only identity when comparing elements.

### Methods for Querying

  • #length (aliased as #size): Returns the count of elements.

  • #empty?: Returns whether the set has no elements.

  • #include? (aliased as #member? and #===): Returns whether a given object is an element in the set.

  • #subset? (aliased as [<=](#method-i-3C-3D)): Returns whether a given object is a subset of the set.

  • #proper_subset? (aliased as [<](#method-i-3C)): Returns whether a given enumerable is a proper subset of the set.

  • #superset? (aliased as [>=](#method-i-3E-3D])): Returns whether a given enumerable is a superset of the set.

  • #proper_superset? (aliased as [>](#method-i-3E)): Returns whether a given enumerable is a proper superset of the set.

  • #disjoint?: Returns true if the set and a given enumerable have no common elements, false otherwise.

  • #intersect?: Returns true if the set and a given enumerable: have any common elements, false otherwise.

  • #compare_by_identity?: Returns whether the set considers only identity when comparing elements.

### Methods for Assigning

  • #add (aliased as #<<): Adds a given object to the set; returns self.

  • #add?: If the given object is not an element in the set, adds it and returns self; otherwise, returns nil.

  • #merge: Merges the elements of each given enumerable object to the set; returns self.

  • #replace: Replaces the contents of the set with the contents of a given enumerable.

### Methods for Deleting

  • #clear: Removes all elements in the set; returns self.

  • #delete: Removes a given object from the set; returns self.

  • #delete?: If the given object is an element in the set, removes it and returns self; otherwise, returns nil.

  • #subtract: Removes each given object from the set; returns self.

  • #delete_if - Removes elements specified by a given block.

  • #select! (aliased as #filter!): Removes elements not specified by a given block.

  • #keep_if: Removes elements not specified by a given block.

  • #reject! Removes elements specified by a given block.

### Methods for Converting

  • #classify: Returns a hash that classifies the elements, as determined by the given block.

  • #collect! (aliased as #map!): Replaces each element with a block return-value.

  • #divide: Returns a hash that classifies the elements, as determined by the given block; differs from #classify in that the block may accept either one or two arguments.

  • #flatten: Returns a new set that is a recursive flattening of self.

\#flatten!:
 Replaces each nested set in +self+ with the elements from that set.

  • #inspect (aliased as #to_s): Returns a string displaying the elements.

  • #join: Returns a string containing all elements, converted to strings as needed, and joined by the given record separator.

  • #to_a: Returns an array containing all set elements.

  • #to_set: Returns self if given no arguments and no block; with a block given, returns a new set consisting of block return values.

### Methods for Iterating

  • #each: Calls the block with each successive element; returns self.

### Other Methods

  • #reset: Resets the internal state; useful if an object has been modified while an element in the set.

Constant Summary collapse

VERSION = 
"1.1.3"
InspectKey =

:nodoc:

:__inspect_key__

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(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}>



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

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) ⇒ Object

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}>



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# File 'lib/set.rb', line 231

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

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



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# File 'lib/set.rb', line 646

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) ⇒ Object 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"}>



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# File 'lib/set.rb', line 636

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

#<=>(set) ⇒ Object

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.



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# File 'lib/set.rb', line 459

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) ⇒ Object

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



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# File 'lib/set.rb', line 680

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

#^(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))`.

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



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

def ^(enum)
  n = self.class.new(enum)
  each { |o| n.add(o) unless n.delete?(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.

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}>



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# File 'lib/set.rb', line 517

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

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 529

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

#classify ⇒ Object

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.



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# File 'lib/set.rb', line 749

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 ⇒ Object

Removes all elements and returns self.

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



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# File 'lib/set.rb', line 319

def clear
  @hash.clear
  self
end

#collect! ⇒ Object Also known as: map!

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



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# File 'lib/set.rb', line 570

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

#compare_by_identity ⇒ Object

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



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# File 'lib/set.rb', line 260

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

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

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 271

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

#delete(o) ⇒ Object

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



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# File 'lib/set.rb', line 535

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.

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 542

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

#delete_if(&block) ⇒ Object

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



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# File 'lib/set.rb', line 549

def delete_if(&block)
  block_given? or return enum_for(__method__) { size }
  # Instead of directly using @hash.delete_if, perform enumeration
  # using self.each that subclasses may override.
  select(&block).each { |o| @hash.delete(o) }
  self
end

#disjoint?(set) ⇒ Boolean

Returns true if the set and the given enumerable 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
Set[1, 2, 3].disjoint? [3, 4]      #=> false
Set[1, 2, 3].disjoint? 4..5        #=> true

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 498

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

#divide(&func) ⇒ Object

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.



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# File 'lib/set.rb', line 777

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

#each(&block) ⇒ 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/set.rb', line 505

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

#empty? ⇒ Boolean

Returns true if the set contains no elements.

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 310

def empty?
  @hash.empty?
end

#eql?(o) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 696

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

#flatten ⇒ Object

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



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# File 'lib/set.rb', line 383

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

#flatten! ⇒ Object

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



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# File 'lib/set.rb', line 389

def flatten!
  replace(flatten()) if any?(Set)
end

#freeze ⇒ Object

:nodoc:



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# File 'lib/set.rb', line 298

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

#hash ⇒ Object

:nodoc:



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# File 'lib/set.rb', line 692

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?

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 399

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

#initialize_clone(orig, **options) ⇒ Object

Clone internal hash.



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# File 'lib/set.rb', line 293

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

#initialize_dup(orig) ⇒ Object

Dup internal hash.



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# File 'lib/set.rb', line 287

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

#inspect ⇒ Object Also known as: to_s

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



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# File 'lib/set.rb', line 817

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

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 476

def intersect?(set)
  case set
  when Set
    if size < set.size
      any?(set)
    else
      set.any?(self)
    end
  when Enumerable
    set.any?(self)
  else
    raise ArgumentError, "value must be enumerable"
  end
end

#join(separator = nil) ⇒ Object

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



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# File 'lib/set.rb', line 809

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

#keep_if(&block) ⇒ Object

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



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# File 'lib/set.rb', line 560

def keep_if(&block)
  block_given? or return enum_for(__method__) { size }
  # Instead of directly using @hash.keep_if, perform enumeration
  # using self.each that subclasses may override.
  reject(&block).each { |o| @hash.delete(o) }
  self
end

#merge(*enums) ⇒ Object

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



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# File 'lib/set.rb', line 601

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

  self
end

#pretty_print(pp) ⇒ Object

:nodoc:



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# File 'lib/set.rb', line 834

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

#pretty_print_cycle(pp) ⇒ Object

:nodoc:



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# File 'lib/set.rb', line 845

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.

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 444

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?(set)
  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.

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 418

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?(self)
  else
    raise ArgumentError, "value must be a set"
  end
end

#reject!(&block) ⇒ Object

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



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# File 'lib/set.rb', line 580

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

#replace(enum) ⇒ Object

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}>



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# File 'lib/set.rb', line 330

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 ⇒ Object

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

Elements will be reindexed and deduplicated.



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# File 'lib/set.rb', line 705

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) ⇒ Object Also known as: filter!

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



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# File 'lib/set.rb', line 589

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

#size ⇒ Object Also known as: length

Returns the number of elements.



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# File 'lib/set.rb', line 304

def size
  @hash.size
end

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

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

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 431

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?(set)
  else
    raise ArgumentError, "value must be a set"
  end
end

#subtract(enum) ⇒ Object

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



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# File 'lib/set.rb', line 615

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.

Returns:

  • (Boolean) 


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# File 'lib/set.rb', line 405

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?(self)
  else
    raise ArgumentError, "value must be a set"
  end
end

#to_a ⇒ Object

Returns an array containing all elements in the set.

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



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# File 'lib/set.rb', line 345

def to_a
  @hash.keys
end

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

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.



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

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

#|(enum) ⇒ Object 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}>



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# File 'lib/set.rb', line 625

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