Complete code example that demonstrates all PEP-8 rules - python

I want my code to be PEP-8 compliant.
However, reading the PEP8-page everytime I forgot any of the rules is time-consuming. Much faster would be if I had a code example, which demonstrates all PEP-8 rules.
Is there any code example out there which does exactly that?

Here's a gist which claims to be a cheatsheet:
https://gist.github.com/RichardBronosky/454964087739a449da04

You could use Eclipse, the last versions (>2.3.0) of Pydev can include the pep8 checker, so the check will be done in real-time. As soon you wrote the code, the checker will verify it.

I tend to look at code from established projects with contributor policies including PEP. Here are some examples:
sklearn:
Feature selection _from_model.py
logistic.py
Gaussian process _gpr.py
Keras: training.py
Flask: sessions.py
In the examples here, Keras and Flask allow lines longer than 80 characters when necessary which seems common in other projects too. scikit-lean seems to conform exactly in the examples I've seen.
I think this is quite a good example for docstring: Napoleon. Though it's Google's take on docstring rather than official Python.

Get PyDev in Eclipse, the new version include support to make sure that your document is PEP8 compliant and will give warnings on each violation.

Use vim/emacs with plugins. I am vim user so only vim link:
http://www.vim.org/scripts/script.php?script_id=2914

Related

Auto-completion & documentation of Python code

Can I use index.d.ts to enable custom code documentation & auto-completion for Python code as we do in JS? if so, how? If not, is there any equivalent for Python?
Yes, there have been various additions to Python over time that allow you to do so.
As mentioned in the comments, https://www.python.org/dev/peps/pep-0526/ and https://www.python.org/dev/peps/pep-0257/ cover this in part.
See also the documentation on type hints here https://docs.python.org/3/library/typing.html
Note that if you wanted to know how to provide type hints for a very specific example, you should have probably included some sample code that needed the hints, but hopefully the above helps.

Automatic testing of examples in documentation

In the end of the SageMath manual they explain why they chose to implement SageMath in Python. One of the items says: "Excellent support for documentation of functions and packages in the source code, including automatic extraction of documentation and automatic testing of all examples. The examples are automatically tested regularly and guaranteed to work as indicated."
This sounds neat, but I haven't found the way to do it. How can I automatically test all the examples that appear in the documentation to my functions?
In principle, you can write your examples using this syntax. Then, you should be able to just do
sage -t path/to/myfile.sage
and apparently that works, given the comment thread!

Static code analysis in Python?

Which helpful static code analysis can you recommend for Python. I believe they are useful for refactoring code.
I know
snakefood for module dependencies
pycallgraph for dynamic call graphs
pylint for bugs
Are there static call analyzers? If I wanted to program a custom one, which would be the easiest way?
What other type of static code checks can you think of? Or maybe even some Python magic like ABCs?
EDIT: I've found that either using http://docs.python.org/3.3/library/ast.html or maybe even http://www.astroid.org/ can be used to program some custom parser. Then one can use graphviz to visualize or even PlantUML for UML graphs.
check out pychecker and pyflakes. There was a famous question to discuss the pylint-pychecker-or-pyflakes
this is a very powerful python type inferencer
https://github.com/yinwang0/pysonar2
it has strong bug check ability but it's not exposed through its interface, but I assume you could do many awesome checks based on it.
Not exactly "static code analyzer" but even a bit more:
http://code.google.com/p/shedskin/
Pysonar2 is a very nice implementation of abstract interpretation to type inference Python projects. My answer to another similar question is here.

Python tool that suggests refactorings

When digging into legacy Python code and writing Python code myself, I often use pylint. I'm also using Clone Digger. I've recently started to use rope, which is a library for automated refactoring.
But I'm looking for something else than rope. I would prefer a tool that just makes suggestions about possible refactorings: names the refactoring, optionally provides a short description of it (great for learning purposes), highlights the code section and lets me do the refactoring myself. Is there such a tool?
Check out bicycle repair man http://bicyclerepair.sourceforge.net/
What is Bicycle Repair Man?
The Bicycle Repair Man project is an attempt to create refactoring browser functionality for python. It is packaged as a library that can be added to IDEs and editors to provide refactoring capabilities. Bindings for Emacs and Vi are included with the package.
Never used it myself, but have read about it. Sounds like what you are looking for.
You might like Pythoscope, an automatic Python unit test generator, which is supposed to help you bootstrap a unit test suite by dynamically executing code.
Also, have you checked out the rope.contrib.codeassist module? It is supposed to automatically propose and perform refactorings of your source code for you.
I don't if that type of tool exists in any specific language, although the concept was mentioned in Martin Fowler's refactoring book (web reference).
The best tool I know of that currently exists is cyclomatic complexity. This article implements a cyclomatic complexity counter for python.
The other easy metric to target is method/function length, number of attributes of objects/classes and number of parameters to functions, if I recall, pylint already counted those.
Oh Forget about your tool, instead use TDD and a good book like refactoring to design patterns by Kerievsky. The problem is that refactoring is a way to improve your code and design, but only You can know what you want to achieve, no refactoring tool can do it for you.
My point is that best way to learn refactoring is to study examples, not to follow some stupid/simple tools, because they wont teach you any sophisticated refactoring nor they will tell you if you have refactoring that compose well with you code.
PS Read Fowler "Refactoring" and Kerievsky "Refactoring to design Patterns" those books are must read when learning refactoring. And they mention simple way to checking if refactoring is needed (smells).
Also consider TDD as good way to ensure that your refs are safe and do not break your code.
Beck "Test-Driven Development by example" is a good book to start with.
And Python have PyUnit for TDD.
NetBeans has an early access version that supports Python, and it is rather nice. It has some basic refactoring tools that I found the be useful. As an added bonus it works on Windows, Linux, Mac OS X and Solaris.
Check it out at:
http://www.netbeans.org/features/python/

How do I use the wx.lib.docview package?

I'm currently working on a simple wxPython app that's essentially document based. So far I've been manually implementing the usual open/save/undo/redo etc etc stuff.
It occurred to me that wxPython must have something to help me out and after a bit of searching revealed the docview package.
At this point though I'm just not quite sure how to hook everything up and get things started. Anyone got any good links or hints about places to start?
The docs seems to be a little thin about this and Robin Dunn's wxPython book doesn't really cover this package at all.
You might take a look at the docviewdemo.py from the wxPython Docs and Demos:
on my machine they are located:
C:\Program Files\wxPython2.8 Docs and Demos\samples\pydocview\
C:\Program Files\wxPython2.8 Docs and Demos\samples\docview\
In addition to the ones mentioned, there is quite an extensive example docview/pydocview in the samples\ide. If you want it to run you will have to make a few code corrections (I have submitted a ticket that outlines the fixes at trac.wxwidgets.org #11237). It is pretty complex but I found it handy to figure out how to do some more complex things. For example, samples\ide\activegrid\tools\ProjectEditor.py is built from scratch and has undo support etc rather than just relying on a control that does everything for you already. That way you can see how things are supposed to be done at the detailed level. The documentation is rather useless in that regard.
If you have decided against using docview/pydocview I have a spreadsheet application built on wxPython that you may find useful as an example. While it does not implement a document view framework it does have some characteristics of it and I've implemented an undo/redo system. Check it out at http://www.missioncognition.net/pysheet/ I'm currently working on a pydocview based app so I expect that to be up on my site eventually.

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