#pyflakes

About style guide of python and linter tool. pep8, pyflakes, flake8, haking, Pyling.

Hello, I have summarized Style guide of python and programming device for coding rules in this entry. I described 5 different tools which are pep8, pyflakes, flake8, haking, Pyling. Since this entry is longer than usual, if you don’t have much time I recommend you to read the chapter of pep8 and flake8. Table of Contents How to use pep8 What is PEP 8 Concept of PEP 8 Running pep8 Output of the…

Fixed PyLint, PyChecker or PyFlakes? #dev #it #asnwer

PyLint, PyChecker or PyFlakes?

I would like to get some feedback on these tools on :

features;

adaptability;

ease of use and learning curve.

Answer: PyLint, PyChecker or PyFlakes?

Well, I am a bit curious, so I just tested the 3 myself right after asking the question ;-)

Ok, this is not a very serious review but here is what I can say :

I tried the tools with the default settings(it’s…

How to: Are there any static analysis tools for Python?

Are there any static analysis tools for Python?

I am starting to use Python (specifically because of Django) and I would like to remove the burden for exhaustive testing by performing some static analysis. What tools/parameters/etc. exist to detect issues at compile time that would otherwise show up during runtime? (type errors are probably the most obvious case of this, but undefined variables…

How to: PyLint, PyChecker or PyFlakes?

PyLint, PyChecker or PyFlakes?

I would like to get some feedback on these tools on :

features;

adaptability;

ease of use and learning curve.

Answer: PyLint, PyChecker or PyFlakes?

Well, I am a bit curious, so I just tested the 3 myself right after asking the question ;-)

Ok, this is not a very serious review but here is what I can say :

I tried the tools with the default settings(it’s…

Each line of a Makefile target is executed in a sub-shell, this has pros and cons, but at least the following side-effect can be observed:

fun: export FOO="wunder bar" echo $$FOO

This doesn't echo "wunder bar" to the cmdline when you run make because the export happens in a different shell then the echo.

You can anyhow set environment variables using the export keyword:

export FOO="wunder bar" fun: echo $FOO

This now echos "wunder bar" to the cmdline when you run make.

So what is problematic with this? The quotes. The environment variable FOO will contain the string "wunder bar" - including the quotes! This happens because export is now the automake keyword, and that means the whole part on the right of the equals sign (=) is the value of the variable named on the left hand side (FOO). And in the example above this includes the quotes.

What happened to me earlier on was that I tried to set an environment variable (PYFLAKES_BUILTINS) which got picked up by pyflakes. I used:

export PYFLAKES_BUILTINS="_" fun: pyflakes file.py

Now, spot the problem.

Solution: pyflakes (correctly) didn't behave as expected (handle _ as a built-in), because the value of the variable was "_", instead of _.

$ export PYFLAKES_BUILTINS="_" $ pyflakes file.py

For syntax ans style checking

Added pyflakes and pep8 with easy_install

sudo easy_install pyflakes

sudo easy_install pep8

Added to ./emacs

(add-to-list 'exec-path "/Library/Frameworks/Python.framework/Versions/2.7/bin/")

and

`;; pyflakes and pep8 (when (load "flymake" t) (defun flymake-pyflakes-init () (let* ((temp-file (flymake-init-create-temp-buffer-copy 'flymake-create-temp-inplace)) (local-file (file-relative-name temp-file (file-name-directory buffer-file-name)))) (list "pyflakes" (list local-file)) (list "pep8" (list local-file)) ))

(add-to-list 'flymake-allowed-file-name-masks '("\.py\'" flymake-pyflakes-init)))

(add-hook 'find-file-hook 'flymake-find-file-hook)`

Maintaining different version of python with:

sudo easy_install virtualenv

View all installed packages:

まず pip で pyflakes をインストールする。

# pip install pyflakes $ which pyflakes /usr/bin/pyflakes

これで pyflakes コマンドが使えるようになった。

文法的に正しい Python スクリプトに対して実行してみる。

#!/usr/bin/env python # -*- coding: utf-8 -*- if __name__ == '__main__': print 'OK!'

上記を valid.py という名前を付けて保存して pyflakes にかける。

$ pyflakes valid.py $

何も出力されない。

今度はさっきのスクリプトの if から ":" (コロン) を抜いて実行してみる。

#!/usr/bin/env python # -*- coding: utf-8 -*- if __name__ == '__main__' print 'OK!'

invalid.py という名前で保存して pyflakes にかける。

$ pyflakes invalid.py invalid.py:5: invalid syntax if __name__ == '__main__' ^

文法がおかしいよ！って教えてくれた。

それ以外にも、使ってないインポートとか無駄なコードを警告してくれたりもする。

#!/usr/bin/env python # -*- coding: utf-8 -*- import os if __name__ == '__main__': print 'OK!'

import os は使われていないので無駄なコード。

$ pyflakes unused.py unused.py:4: 'os' imported but unused

特定のディレクトリ以下を一気にチェックしたいときはワンライナーを書けば良いかな。

$ find . -name \*.py | xargs pyflakes ./invalid.py:5: invalid syntax if __name__ == '__main__' ^ ./unused.py:4: 'os' imported but unused

IDE だとエディタに最初から組み込まれてたりするけど、そうでないときは便利かな。

I started using Vim last fall and haven't looked back. It's been installed on every box I've ever SSHed in to, so changing code on a production server (Gasp!) is a breeze. I know that I've barely scraped the surface of Vim's possibilities, but I already feel like I'm pretty efficient with it and I long for it's toolset on the rare occasion that I work in NetBeans. For anyone interested, my Editor/IDE progression has been: NotePad > Komodo Edit > NetBeans > Vim. NetBeans is great but massive and I got sick and tired of it changing for updates and bogging down my aging laptop, so I learned Vim.

PyFlakes is defined at the Python Package Index as such: Pyflakes is program to analyze Python programs and detect various errors. It works by parsing the source file, not importing it, so it is safe to use on modules with side effects. It's also much faster. It's a great tool to keep Python code tidy, but running it manually gets old:

$ pyflakes my_script.py