class Set

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}>

# File lib/set.rb, line 228
def self.[](*ary)
  new(ary)
end

See as_json.

# File ext/json/lib/json/add/set.rb, line 9
def self.json_create(object)
  new object['a']
end

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}>

# File lib/set.rb, line 243
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

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"}>

# File lib/set.rb, line 640
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

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"}>

# File lib/set.rb, line 630
def -(enum)
  dup.subtract(enum)
end

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.

# File lib/set.rb, line 453
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

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

# File lib/set.rb, line 674
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

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"}>

# File lib/set.rb, line 661
def ^(enum)
  n = Set.new(enum)
  each { |o| n.add(o) unless n.delete?(o) }
  n
end

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}>

# File lib/set.rb, line 511
def add(o)
  @hash[o] = true
  self
end

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

# File lib/set.rb, line 523
def add?(o)
  add(o) unless include?(o)
end

Methods Set#as_json and Set.json_create may be used to serialize and deserialize a Set object; see Marshal.

Method Set#as_json serializes self, returning a 2-element hash representing self:

require 'json/add/set'
x = Set.new(%w/foo bar baz/).as_json
# => {"json_class"=>"Set", "a"=>["foo", "bar", "baz"]}

Method JSON.create deserializes such a hash, returning a Set object:

Set.json_create(x) # => #<Set: {"foo", "bar", "baz"}>

# File ext/json/lib/json/add/set.rb, line 28
def as_json(*)
  {
    JSON.create_id => self.class.name,
    'a'            => to_a,
  }
end

Classifies the set by the return value of the given block and returns a hash of {value => 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.

# File lib/set.rb, line 743
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

Removes all elements and returns self.

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

# File lib/set.rb, line 316
def clear
  @hash.clear
  self
end

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

# File lib/set.rb, line 564
def collect!
  block_given? or return enum_for(__method__) { size }
  set = self.class.new
  each { |o| set << yield(o) }
  replace(set)
end

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

# File lib/set.rb, line 257
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

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

# File lib/set.rb, line 268
def compare_by_identity?
  @hash.respond_to?(:compare_by_identity?) && @hash.compare_by_identity?
end

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

# File lib/set.rb, line 529
def delete(o)
  @hash.delete(o)
  self
end

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

# File lib/set.rb, line 536
def delete?(o)
  delete(o) if include?(o)
end

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

# File lib/set.rb, line 543
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

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

# File lib/set.rb, line 492
def disjoint?(set)
  !intersect?(set)
end

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.

# File lib/set.rb, line 771
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

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

# File lib/set.rb, line 499
def each(&block)
  block_given? or return enum_for(__method__) { size }
  @hash.each_key(&block)
  self
end

Returns true if the set contains no elements.

# File lib/set.rb, line 307
def empty?
  @hash.empty?
end

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

# File lib/set.rb, line 377
def flatten
  self.class.new.flatten_merge(self)
end

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

# File lib/set.rb, line 383
def flatten!
  replace(flatten()) if any?(Set)
end

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?

# File lib/set.rb, line 393
def include?(o)
  @hash[o]
end

Clone internal hash.

# File lib/set.rb, line 290
def initialize_clone(orig, **options)
  super
  @hash = orig.instance_variable_get(:@hash).clone(**options)
end

Dup internal hash.

# File lib/set.rb, line 284
def initialize_dup(orig)
  super
  @hash = orig.instance_variable_get(:@hash).dup
end

Returns a string containing a human-readable representation of the set (“#<Set: {element1, element2, …}>”).

# File lib/set.rb, line 811
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

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

# File lib/set.rb, line 470
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

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

# File lib/set.rb, line 803
def join(separator=nil)
  to_a.join(separator)
end

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

# File lib/set.rb, line 554
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

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

# File lib/set.rb, line 595
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

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

# File lib/set.rb, line 438
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

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

# File lib/set.rb, line 412
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

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

# File lib/set.rb, line 574
def reject!(&block)
  block_given? or return enum_for(__method__) { size }
  n = size
  delete_if(&block)
  self if size != n
end

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}>

# File lib/set.rb, line 327
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

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

Elements will be reindexed and deduplicated.

# File lib/set.rb, line 699
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

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

# File lib/set.rb, line 583
def select!(&block)
  block_given? or return enum_for(__method__) { size }
  n = size
  keep_if(&block)
  self if size != n
end

Returns the number of elements.

# File lib/set.rb, line 301
def size
  @hash.size
end

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

# File lib/set.rb, line 425
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

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

# File lib/set.rb, line 609
def subtract(enum)
  do_with_enum(enum) { |o| delete(o) }
  self
end

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

# File lib/set.rb, line 399
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

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]

# File lib/set.rb, line 342
def to_a
  @hash.keys
end

Returns a JSON string representing self:

require 'json/add/set'
puts Set.new(%w/foo bar baz/).to_json

Output:

{"json_class":"Set","a":["foo","bar","baz"]}

# File ext/json/lib/json/add/set.rb, line 44
def to_json(*args)
  as_json.to_json(*args)
end

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.

# File lib/set.rb, line 351
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

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}>

# File lib/set.rb, line 619
def |(enum)
  dup.merge(enum)
end