Ruby puzzle

transform_hash.rb

describe '#transform_hash' do
  it 'transforms a single entry hash' do
    transform_hash(a: [1, 0]).should == [[1], [0]]
  end

  it 'transforms a double entry hash' do
    transform_hash(a: [1, 0], b: [0, 1]).should == [[1, 0], [0, 1]]
  end

  it 'transforms a multiple entry hash' do
    transform_hash(
      a: [1, 0], 
      b: [0, 1],
      c: [1, 1]
    ).should == [[1, 0, 1], [0, 1, 1]]
  end
end


def identity_stream(value)
  Enumerator.new do |yielder|
    while true
      yielder.yield(value)
    end
  end
end

def transform_hash(hash)
  hash.values.reverse.reduce(identity_stream([])) {|x, y|
    y.zip(x).map(&:flatten)
  }
end

Fail, never mind. For some reason the specs are running green all the time. Misconfiguration on my part ...

def transform_hash(hash)
  hash.values.transpose
end

:)

Yep .. nice.

Maybe try the simplest approach possible? (I haven't tried if it really works)

def transform_hash(hash)
  x, y = [], []
  hash.values.each do |i, j|
    x << i
    y << j
  end
  [x,y]
end

Ah, love the transpose one. Killer. :D