Set#divide

() { (A, A) -> ::Hash::_Key } -> ::Set[self]

() { (A) -> ::Hash::_Key } -> ::Set[self]

divide(&func)

# File tmp/rubies/ruby-3.4.1/lib/set.rb, line 774
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

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).

Example

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.

See also #disjoint? #each #difference #empty? also in 4.1 · 4.0 · 3.3 · 3.2 · 3.1 · 3.0

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