python: get directory two levels up

Question

Ok...I dont know where module x is, but I know that I need to get the path to the directory two levels up.

So, is there a more elegant way to do:

Answer 1

I don't yet see a viable answer for 2.7 which doesn't require installing additional dependencies and also starts from the file's directory. It's not nice as a single-line solution, but there's nothing wrong with using the standard utilities.

import os

grandparent_dir = os.path.abspath(  # Convert into absolute path string
    os.path.join(  # Current file's grandparent directory
        os.path.join(  # Current file's parent directory
            os.path.dirname(  # Current file's directory
                os.path.abspath(__file__)  # Current file path
            ),
            os.pardir
        ),
        os.pardir
    )
)

print grandparent_dir

And to prove it works, here I start out in ~/Documents/notes just so that I show the current directory doesn't influence outcome. I put the file grandpa.py with that script in a folder called "scripts". It crawls up to the Documents dir and then to the user dir on a Mac.

(testing)AlanSE-OSX:notes AlanSE$ echo ~/Documents/scripts/grandpa.py 
/Users/alancoding/Documents/scripts/grandpa.py
(testing)AlanSE-OSX:notes AlanSE$ python2.7 ~/Documents/scripts/grandpa.py 
/Users/alancoding

This is the obvious extrapolation of the answer for the parent dir. Better to use a general solution than a less-good solution in fewer lines.

Answer 2

Personally, I find that using the os module is the easiest method as outlined below. If you are only going up one level, replace ('../..') with ('..').

    import os
    os.chdir('../..')

--Check:
    os.getcwd()

Answer 3

More cross-platform implementation will be:

import pathlib
two_up = (pathlib.Path(__file__) / ".." / "..").resolve()

Using parent is not supported on Windows. Also need to add .resolve(), to:

Make the path absolute, resolving all symlinks on the way and also normalizing it (for example turning slashes into backslashes under Windows)

Answer 4

The best solution (for python >= 3.4) when executing from any directory is:

from pathlib import Path
two_up = Path(__file__).resolve().parents[1]

Answer 5

You can use this as a generic solution:

import os

def getParentDir(path, level=1):
  return os.path.normpath( os.path.join(path, *([".."] * level)) )

Answer 6

I was going to add this just to be silly, but also because it shows newcomers the potential usefulness of aliasing functions and/or imports.

Having written it, I think this code is more readable (i.e. lower time to grasp intention) than the other answers to date, and readability is (usually) king.

from os.path import dirname as up

two_up = up(up(__file__))

Note: you only want to do this kind of thing if your module is very small, or contextually cohesive.