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

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


There's numpy.broadcast_to (new in Numpy 1.10.0):

field3d_mask = np.broadcast_to(field2d > 0.3, field3d.shape)


Without the loop you could write it as:

field3d_mask[:,:,:] = field2d[np.newaxis,:,:] > 0.3

For example:

field3d_mask_1 = np.zeros(field3d.shape, dtype=bool)field3d_mask_2 = np.zeros(field3d.shape, dtype=bool)for t in range(nt):    field3d_mask_1[t,:,:] = field2d > 0.3field3d_mask_2[:,:,:] = field2d[np.newaxis,:,:] > 0.3print((field3d_mask_1 == field3d_mask_2).all())

gives:

True