Class: Set

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

Included Modules

Enumerable

Public Class methods

[](*ary)

Creates a new set containing the given objects.

[Source]

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

new(enum = nil) {|o| ...}

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

&(enum)

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

[Source]

# File set.rb, line 295
  def &(enum)
    enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
    n = self.class.new
    enum.each { |o| include?(o) and n.add(o) }
    n
  end

+(enum)

Alias for #|

-(enum)

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

[Source]

# File set.rb, line 287
  def -(enum)
    enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
    dup.subtract(enum)
  end

<<(o)

Alias for add

==(set)

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 315
  def ==(set)
    equal?(set) and return true

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

    set.all? { |o| include?(o) }
  end

^(enum)

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 306
  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

add(o)

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

[Source]

# File set.rb, line 199
  def add(o)
    @hash[o] = true
    self
  end

add?(o)

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 207
  def add?(o)
    if include?(o)
      nil
    else
      add(o)
    end
  end

classify() {|o| ...}

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 344
  def classify # :yields: o

    h = {}

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

    h
  end

clear()

Removes all elements and returns self.

[Source]

# File set.rb, line 97
  def clear
    @hash.clear
    self
  end

collect!() {|o| ...}

Do collect() destructively.

[Source]

# File set.rb, line 240
  def collect!
    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 several items at once.

[Source]

# File set.rb, line 217
  def delete(o)
    @hash.delete(o)
    self
  end

delete?(o)

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 224
  def delete?(o)
    if include?(o)
      delete(o)
    else
      nil
    end
  end

delete_if() {|o| ...}

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

[Source]

# File set.rb, line 234
  def delete_if
    @hash.delete_if { |o,| yield(o) }
    self
  end

difference(enum)

Alias for #-

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).

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 371
  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

dup()

Duplicates the set.

[Source]

# File set.rb, line 77
  def dup
    myhash = @hash
    self.class.new.instance_eval {
      @hash.replace(myhash)
      self
    }
  end

each() {|o| ...}

Calls the given block once for each element in the set, passing the element as parameter.

[Source]

# File set.rb, line 192
  def each
    @hash.each_key { |o| yield(o) }
    self
  end

empty?()

Returns true if the set contains no elements.

[Source]

# File set.rb, line 92
  def empty?
    @hash.empty?
  end

flatten()

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

[Source]

# File set.rb, line 142
  def flatten
    self.class.new.flatten_merge(self)
  end

flatten!()

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 148
  def flatten!
    if detect { |e| e.is_a?(Set) }
      replace(flatten())
    else
      nil
    end
  end

include?(o)

Returns true if the set contains the given object.

[Source]

# File set.rb, line 157
  def include?(o)
    @hash.include?(o)
  end

inspect()

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

[Source]

# File set.rb, line 403
  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?

merge(enum)

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

[Source]

# File set.rb, line 257
  def merge(enum)
    if enum.class == self.class
      @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

proper_subset?(set)

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

[Source]

# File set.rb, line 184
  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

proper_superset?(set)

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

[Source]

# File set.rb, line 170
  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

reject!() {|o| ...}

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

[Source]

# File set.rb, line 249
  def reject!
    n = size
    delete_if { |o| yield(o) }
    size == n ? nil : self
  end

replace(enum)

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

[Source]

# File set.rb, line 104
  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

size()

Returns the number of elements.

[Source]

# File set.rb, line 86
  def size
    @hash.size
  end

subset?(set)

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

[Source]

# File set.rb, line 177
  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

subtract(enum)

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

[Source]

# File set.rb, line 270
  def subtract(enum)
    enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
    enum.each { |o| delete(o) }
    self
  end

superset?(set)

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

[Source]

# File set.rb, line 163
  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

to_a()

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

[Source]

# File set.rb, line 117
  def to_a
    @hash.keys
  end

union(enum)

Alias for #|

|(enum)

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

[Source]

# File set.rb, line 278
  def |(enum)
    enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
    dup.merge(enum)
  end

Set ^(Class)

Example

Methods

Included Modules

Public Class methods

Public Instance methods

Set (Class)

Example

Methods

Included Modules

Public Class methods

Public Instance methods

Set ^(Class)