Files and Directories

Import io for open.

Import os for chdir, getcwd, listdir, mkdir, remove, rename, walk, etc.

Import os.path for basename, dirname, exists, isdir, getmtime, etc.

Files

import io
# Default mode is 'rt' (read, text).
with io.open('my_file.txt') as f:
    for line in f:
        # get lines one at a time, each still having a newline at the end
        ...
    # or
    lines = f.readlines()  # leaves the newlines at the end of each line
    # or
    all_of_it = f.read()
    # do stuff

and the file is automatically closed when we leave the with block.

Directory Walking

import os
for (the_dir, dirs, files) in os.walk('.'):
    # Here, `the_dir` will always start with a ".".
    print('The dir:  ', the_dir)
    print('Dirs in it: ', dirs)
    print('Files in it:', files)
    print('-' * 10)

Note that while walking the dirs, cwd does not change.

If you want to keep track of how deep you are, you can count slashes:

the_dir.count("/")