Mask a 3d array with a 2d mask in numpy

Question

I have a 3-dimensional array that I want to mask using a 2-dimensional array that has the same dimensions as the two rightmost of the 3-dimensional array. Is there a way to do this without writing the following loop?

import numpy as np  nx = 2 nt = 4  field3d = np.random.rand(nt, nx, nx) field2d = np.random.rand(nx, nx)  field3d_mask = np.zeros(field3d.shape, dtype=bool)  for t in range(nt):     field3d_mask[t,:,:] = field2d > 0.3  field3d = np.ma.array(field3d, mask=field3d_mask)  print field2d print field3d