Class Set
In: set.rb
Parent: Object

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.

Several methods accept any Enumerable object (implementing each) for greater flexibility: new, replace, merge, subtract, |, &, -, ^.

The equality of each couple of elements is determined according to Object#eql? and Object#hash, since Set uses Hash as storage.

Finally, if you are using class Set, you can also use Enumerable#to_set for convenience.

Example

  require 'set'
  s1 = Set.new [1, 2]                   # -> #<Set: {1, 2}>
  s2 = [1, 2].to_set                    # -> #<Set: {1, 2}>
  s1 == s2                              # -> true
  s1.add("foo")                         # -> #<Set: {1, 2, "foo"}>
  s1.merge([2, 6])                      # -> #<Set: {6, 1, 2, "foo"}>
  s1.subset? s2                         # -> false
  s2.subset? s1                         # -> true

Methods

&   +   -   <<   ==   []   ^   add   add?   classify   clear   collect!   delete   delete?   delete_if   difference   divide   each   empty?   flatten   flatten!   include?   initialize_copy   inspect   intersection   length   map!   member?   merge   new   proper_subset?   proper_superset?   reject!   replace   size   subset?   subtract   superset?   to_a   union   |  

Included Modules

Enumerable

Public Class methods

Creates a new set containing the given objects.

[Source]

# File set.rb, line 55
  def self.[](*ary)
    new(ary)
  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.

[Source]

# File set.rb, line 64
  def initialize(enum = nil, &block) # :yields: o
    @hash ||= Hash.new

    enum.nil? and return

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

Public Instance methods

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

[Source]

# File set.rb, line 291
  def &(enum)
    enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
    n = self.class.new
    enum.each { |o| n.add(o) if include?(o) }
    n
  end
+(enum)

Alias for #|

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

[Source]

# File set.rb, line 283
  def -(enum)
    enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
    dup.subtract(enum)
  end
<<(o)

Alias for add

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

[Source]

# File set.rb, line 311
  def ==(set)
    equal?(set) and return true

    set.is_a?(Set) && size == set.size or return false

    hash = @hash.dup
    set.all? { |o| hash.include?(o) }
  end

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

[Source]

# File set.rb, line 302
  def ^(enum)
    enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
    n = dup
    enum.each { |o| if n.include?(o) then n.delete(o) else n.add(o) end }
    n
  end

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

[Source]

# File set.rb, line 195
  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.

[Source]

# File set.rb, line 203
  def add?(o)
    if include?(o)
      nil
    else
      add(o)
    end
  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.

e.g.:

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

[Source]

# File set.rb, line 342
  def classify # :yields: o
    h = {}

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

    h
  end

Removes all elements and returns self.

[Source]

# File set.rb, line 93
  def clear
    @hash.clear
    self
  end

Do collect() destructively.

[Source]

# File set.rb, line 236
  def collect!
    set = self.class.new
    each { |o| set << yield(o) }
    replace(set)
  end

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

[Source]

# File set.rb, line 213
  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.

[Source]

# File set.rb, line 220
  def delete?(o)
    if include?(o)
      delete(o)
    else
      nil
    end
  end

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

[Source]

# File set.rb, line 230
  def delete_if
    @hash.delete_if { |o,| yield(o) }
    self
  end
difference(enum)

Alias for #-

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).

e.g.:

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

[Source]

# File set.rb, line 369
  def divide(&func)
    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.

[Source]

# File set.rb, line 188
  def each
    @hash.each_key { |o| yield(o) }
    self
  end

Returns true if the set contains no elements.

[Source]

# File set.rb, line 88
  def empty?
    @hash.empty?
  end

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

[Source]

# File set.rb, line 138
  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.

[Source]

# File set.rb, line 144
  def flatten!
    if detect { |e| e.is_a?(Set) }
      replace(flatten())
    else
      nil
    end
  end

Returns true if the set contains the given object.

[Source]

# File set.rb, line 153
  def include?(o)
    @hash.include?(o)
  end

Copy internal hash.

[Source]

# File set.rb, line 77
  def initialize_copy(orig)
    @hash = orig.instance_eval{@hash}.dup
  end

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

[Source]

# File set.rb, line 401
  def inspect
    ids = (Thread.current[InspectKey] ||= [])

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

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

Alias for #&

length()

Alias for size

map!()

Alias for collect!

member?(o)

Alias for include?

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

[Source]

# File set.rb, line 253
  def merge(enum)
    if enum.is_a?(Set)
      @hash.update(enum.instance_eval { @hash })
    else
      enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
      enum.each { |o| add(o) }
    end

    self
  end

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

[Source]

# File set.rb, line 180
  def proper_subset?(set)
    set.is_a?(Set) or raise ArgumentError, "value must be a set"
    return false if set.size <= size
    all? { |o| set.include?(o) }
  end

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

[Source]

# File set.rb, line 166
  def proper_superset?(set)
    set.is_a?(Set) or raise ArgumentError, "value must be a set"
    return false if size <= set.size
    set.all? { |o| include?(o) }
  end

Equivalent to Set#delete_if, but returns nil if no changes were made.

[Source]

# File set.rb, line 245
  def reject!
    n = size
    delete_if { |o| yield(o) }
    size == n ? nil : self
  end

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

[Source]

# File set.rb, line 100
  def replace(enum)
    if enum.class == self.class
      @hash.replace(enum.instance_eval { @hash })
    else
      enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
      clear
      enum.each { |o| add(o) }
    end

    self
  end

Returns the number of elements.

[Source]

# File set.rb, line 82
  def size
    @hash.size
  end

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

[Source]

# File set.rb, line 173
  def subset?(set)
    set.is_a?(Set) or raise ArgumentError, "value must be a set"
    return false if set.size < size
    all? { |o| set.include?(o) }
  end

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

[Source]

# File set.rb, line 266
  def subtract(enum)
    enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
    enum.each { |o| delete(o) }
    self
  end

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

[Source]

# File set.rb, line 159
  def superset?(set)
    set.is_a?(Set) or raise ArgumentError, "value must be a set"
    return false if size < set.size
    set.all? { |o| include?(o) }
  end

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

[Source]

# File set.rb, line 113
  def to_a
    @hash.keys
  end
union(enum)

Alias for #|

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

[Source]

# File set.rb, line 274
  def |(enum)
    enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
    dup.merge(enum)
  end

[Validate]