PEP8

Resources

• PEP8
• flake8
• black
• isort

Homework

1. update your forked repo from my repo(ref)
2. following 01_git, create a new branch LAST#_04pep8 (ex: pan667_04pep8) in your forked repo
3. activate the environment you created in 03_conda
4. install flake8, black, and isort
5. take a look at file setup.cfg and try to understand each setting for flake8
6. copy the file code.py to submissions/ and rename it as LAST#.py
7. run flake8 on LAST#.py and you will see some warnings
8. In the warnings, you should see line 33, 34, and 35 are too long. Open LAST#.py and you should see these three lines correspond to three dummy lists (if you use vim to open the file, type :set nu to show the line numbers). Now add something on these three lines to make flake8 ignore them. Save the file and run flake8 again, you should see the warnings are gone.
9. run black --help and go through the meaning of each option (flag)
10. run black with diff and color flag and set the line length to 100. These two flags will show the difference without making modification yet. You should see black is trying to fix three dummy lists again. Open LAST#.py and add something on these three lines to make black ignore them. Save the file and run black with same flags again, you should see they are ignored.
11. run black with line length 100 on the file to make modificatoin in place
12. run flake8 again and you should see some warnings were fixed by black
13. take a look at file setup.cfg and try to understand each setting for isort
14. run isort with flag diff to review the modification first and run isort again to modify the file in place (similar to black)
15. run flake8 again and you should still see some warnings. This means black and isort can't fix everything.
16. fix the code yourself unitil flake8 shows no warnings
17. finally run black with line length 100, isort, and flake8 again because you may touch something in the previous step
18. stage changes, commit with the message "learning pep8", push and submit a pr