Вот, пожалуйста:
input = <<INPUT
null,
3.28,
null,
null,
null,
1.91,
2.83,
null,
9.06,
null,
3.80,
6.42,
null,
INPUT
result = input.split.map(&:to_f)
=> [0.0, 3.28, 0.0, 0.0, 0.0, 1.91, 2.83, 0.0, 9.06, 0.0, 3.8, 6.42, 0.0]
result.delete(0.0)
=> 0.0
result
=> [3.28, 1.91, 2.83, 9.06, 3.8, 6.42]