How to step one folder back/higher in Python

The aim of this playbook🏁 is to outline the step back when navigating relatively with Python.

1. steps for step-back

""" from a script in ./helpers reaching for files in ../assets """
assets_dir = os.path.abspath(os.path.join(os.path.dirname(__file__), '..', 'assets'))

1. __file__ returns the absolute path of the script
2. os.path.dirname(__file__) returns the abs path of its parent folder (project root)
3. os.path.join() concatenates the previous, with a step-back control statement, and target folder
4. os.path.abspath() normalizes

2. on os.path.join()

• there are two control statements
• . do nothing
• .. step-back
• Do not combine paths using string concatenation +
• Use only os.path.join()
• Why? Different computers represent paths in different ways.
• E.g. Windows uses \ as a separator, while Unix (Mac and Linux) uses /
• in other words, when you see os.path.join() it means someone is concatenating a file-path

3. on os.path.abspath(path)

os.path.abspath(path)
---
Return a normalized absolutized version of the pathname path. 
On most platforms, this is equivalent to calling the function normpath() as follows: 
normpath(join(os.getcwd(), path)).

— from https://docs.python.org/3/library/os.path.html#os.path.abspath

4. sources

• Navigating the filesystem with relative paths at the command line — Opensource.com
• https://docs.python.org/3/library/os.path.html#os.path.abspath
• Python os module open file above current directory with relative path — Stack Overflow