os

遍历该目录结构的文件，使用os.walk('a')

import os

for root, dirs, files in os.walk("a", topdown=True):
    for name in files:
        print(os.path.join(root, name))

输出：a\b\1.py
a\b\2.py
a\b\d\1.py
a\b\d\2.py
a\c\1.py
a\c\2.py