如何优雅的只遍历一次 list 来生成多个衍生 list

Question

class Something:
  def __init__(self, a, b):
    self.a = a
    self.b = b


somethings = [Something(i, i * i) for i in range(10)]

# 有没有办法仅遍历一次 somethings，并优雅的生成下面两个 list
a_s = [something.a for something in somethings]
b_s = [something.b for something in somethings]

print a_s
print b_s

Answer 1

a_s, b_s = zip(*map(lambda sth: (sth.a, sth.b), somethings))

Answer 2

不用列表解析很好实现，优雅的要求好像达不到。

a_s, b_s =[],[]
for something in somethings:
    a_s.append(something.a)
    b_s.append(something.b) 

Answer 3

a_s, b_s = [], []
[(a_s.append(something.a), b_s.append(something.b)) for something in somethings]

Answer 4

from numpy import array
a_s, b_s = numpy.array([(something.a,something.b) for something in somethings]).T