1. Coding Standards

  • Python code style outlined in PEP8

  • Python section of the NCEP Coding Standards

  • NCO WCOSS Implementation Standards for directory structure and script naming conventions

  • Doxygen, Python docstrings, and Sphinx for documentation

  • NOTE: Please do not use f-strings in the run_metplus.py file so that the Python version check can notify the user of the incorrect version. Using Python 3.5 or earlier will output the SyntaxError from the f-string instead of the useful error message.

1.1. Python code analysis tools


1.1.1. pylint


pip install pylint or conda install pylint


checks for code errors

pylint pep8 code-to-analyze will check for errors as well as PEP-8 style code

1.1.2. pyflakes

pip install pyflakes or conda install pyflakes

parses code rather than importing code, therefore OK to use on modules with side-effects

checks for code errors

faster than pylint


flake8 is wrapper to pyflakes, performs PEP-8 style checking in addition to error checking

1.1.3. vulture

checks for unused imports, variables, methods, classed ie "dead code"

pip install vulture or conda install vulture


Dynamic (run-time):

1.1.4. cpde-coverage analysis

Useful when running unit tests to determine whether tests are executing all possible branches, loops, etc.

1.1.5. figleaf

http://darcs.idyll.org/~t/projects/figleaf/doc/ Checking for God objects and God methods:

(from Chapter 4 of “How to Make Mistakes in Python”, Mike Pirnat)

find . -name "*.py" -exec wc -l {} \; | sort -g -r
    for all Python source files, order by size
    anything over 1000 lines is worth investigating (as general rule of thumb)

grep "^class " mybigmodule.py |wc -l
    counts the number of classes defined in mybigmodule.py

grep "\sdef " mybigmodule.py |wc -l

    counts the number of methods defined within a class or other function (ie at some level of indentation) in mybigmodule.py

    try this if the above doesn't work: grep "def " mybigmodule.py |wc -l

A high ratio of methods to classes warrants investigation (what constitutes a high ratio- 10:1, 5:1???)