Python,例如有两个一维数组，怎么变成二维数组？

a = [ 1,2,3,4,5,6]

b = [7,8,9,10,11,12]

c = numpy.vstack((a,b)).T

然后c就等于[ [1,7], [2,8], [3,9], [4,10], [5,11], [6,12] ]