如果你想懒惰地做,这里有一些代码可以做到这一点:
def merge(*args)
args.map!(&:lazy)
Enumerator.new do |yielder|
while num = args.map(&:peek).min
count = 0
while list = args.find { |l| l.peek == num }
list.next
list.peek rescue args.delete list
count += 1
end
yielder.yield [num, count]
end
end
end
s1 = [1, 1, 2, 3, 3, 3, 4]
s2 = [1, 2, 2, 2, 2, 2, 3, 3, 4]
s3 = [1, 2, 3, 3, 3, 3, 4, 4, 4]
s4 = (0..1.0/0)
merge(s1, s2, s3, s4).take(20)
# => [[0, 1], [1, 5], [2, 8], [3, 10], [4, 6], [5, 1], [6, 1], [7, 1], [8, 1], [9, 1], [10, 1], [11, 1], [12, 1], [13, 1], [14, 1], [15, 1], [16, 1], [17, 1], [18, 1], [19, 1]]