python遍历某个文件夹下的所有子文件夹及文件

import os
rootdir = '/media/dell/D/qcc/code/pointnet/pointnet_2021331/pointnet-master/data/S3DIS/Stanford3dDataset_v1.2_Aligned_Version'
for root,dirs,files in os.walk(rootdir):
    for dir in dirs:
        print(os.path.join(root,dir))
    for file in files:
        print(os.path.join(root,file))

 root变量循环改变。