目录下的多个文件夹里的内容合并到一个文件夹

import os,shutil
path="源路径"
topath="目标路径"
n=0
for root,dir,file in os.walk(path,topdown="False"):
    if len(file)!=0:
        for filename in file:
            shutil.copyfile(os.path.join(root,filename),os.path.join(topath,filename))
            n=n+1
            if n%10000==1:
                print(n)