How can I change directory with Python pathlib

问题:

What is the intended way to change directory using the Python pathlib (Documentation) functionality?

Lets assume I create a Path object as follows:

from pathlib import Path
path = Path('/etc')

Currently I just know the following, but that seems to undermine the idea of pathlib.

import os
os.chdir(str(path))

回答1:

Based on the comments I realized that pathlib does not help changing directories and that directory changes should be avoided if possible.

Since I needed to call bash scripts outside of Python from the correct directory, I opted for using a context manager for a cleaner way of changing directories similar to this answer:

import os
import contextlib
from pathlib import Path

@contextlib.contextmanager
def working_directory(path):
    """Changes working directory and returns to previous on exit."""
    prev_cwd = Path.cwd()
    os.chdir(path)
    try:
        yield
    finally:
        os.chdir(prev_cwd)

A good alternative is to use the cwd parameter of the subprocess.Popen class as in this answer.

If you are using Python <3.6 and path is actually a pathlib.Path, you need str(path) in the chdir statements.

回答2:

In the Python 3.6 or above, os.chdir() can deal with Path object directly. In fact, the Path object can replace most str paths in standard libraries.

os.chdir(path) Change the current working directory to path.

This function can support specifying a file descriptor. The descriptor must refer to an opened directory, not an open file.

New in version 3.3: Added support for specifying path as a file descriptor on some platforms.

Changed in version 3.6: Accepts a path-like object.

import os
from pathlib import Path

path = Path('/etc')
os.chdir(path)

This may help in the future projects which do not have to be compatible with 3.5 or below.

回答3:

For those who do not fear a third-party library:

$ pip install path.py

then:

from path import Path

# Changing the working directory:
with Path("somewhere"):
    # cwd in now `somewhere`
    ...

or if you want to do it without the context manager:

Path("somewhere").cd()
# cwd in now `somewhere`