Python

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Default modes[edit]

There are a number of python modes for Emacs. fgallina's python.el is the python.el included in Emacs 24.2 and onwards.

All-in-one solutions[edit]

emacs-for-python[edit]

emacs-for-python is a bundle of the above modes (and more), and it's an easy way to turn Emacs into a Python IDE.

emacs-for-python at github

Elpy[edit]

Elpy is a collection of elisp packages for Python too.

https://github.com/jorgenschaefer/elpy/wiki/Features


Auto-Completion[edit]

rope & ropemacs[edit]

rope is a library for refactoring and manipulating Python code. ropemacs is an Emacs interface to the rope library.

rope homepage

ropemacs homepage

Jedi[edit]

Jedi.el is a Python auto-completion package for Emacs. It aims at helping your Python coding in a non-destructive way. It also helps you to find information about Python objects, such as docstring, function arguments and code location.

Jedi is simple to install and it works out of the box.

See screenshots and get the full documentation : http://tkf.github.io/emacs-jedi/released/

Jedi's official page: http://jedi.jedidjah.ch/en/latest/

Installation[edit]

Install Jedi.el via el-get, Marmalade or MELPA (see install for more info) and add this to your Emacs configuration:

   (add-hook 'python-mode-hook 'jedi:setup)
   (setq jedi:setup-keys t)                      ; optional
   (setq jedi:complete-on-dot t)                 ; optional

or call M-x jedi:setup

Note: it's nice to use it in a python interpreter inside emacs :)

Anaconda[edit]

Anaconda-mode is a mode for code navigation, documentation lookup and completion for Python.

It runs on emacs 24.3 with python >= 2.6.

It provides:

  • context-sensitive code completion for Python
  • jump to definition
  • find references
  • view documentation
  • virtualenv management

The package is available in MELPA. For more information, read its documentation.

Code Checker[edit]

Flymake[edit]

flymake is a on-the-fly syntax checker for Emacs. We can use it alongside with flyspell.

To run pep8, pylint, pyflakes and unit-tests (with nose), you can be interested in using flymake-python.

Don't forget about pylint too.

Indexing sources: ctags, cscope, pycscope[edit]

etags, ctags[edit]

Etags (Exuberant Ctags) generates an index (or tag) file of language objects found in source files that allows these items to be quickly and easily located by a text editor or other utility. A tag signifies a language object for which an index entry is available (or, alternatively, the index entry created for that object). Etags is a multilingual implementation of ctags.

The primary use for the tags files is looking up class/method/function/constant/etc declaration/definitions. Cscope is more powerful (see below).

usage[edit]

Generate the tags with this command at the root of your project:

    find . -name "*.py" -print | etags -

it creates the file TAGS.

Note that projects like Projectile or Helm provide an integrated use of etags (finding one, re-generating the index, etc).

cscope[edit]

cscope is a much more powerful beast. While it operates on more or less the same principle (generating a file of useful metadata) it allows you do some fancier things like find all references to a symbol, see where a function is being invoked, etc.+ (you can find definitions as well).

It was originally designed for C and C++, but thanks to version 0.3 of pycscope, pythonistas can make use of it.

usage[edit]

The following commands should get you running:

   apt-get install cscope
   pip install pycscope
   # in project base dir:
   find . -name '*.py' > cscope.files
   cscope -R 

now install the xcscope emacs package with ELPA and require it:

   (require 'xcscope)

When done, you can either enable the mode with cscope-minor-mode (which will add a menu you are free to explore) or call some functions like M-x cscope-find-global-definition, M-x cscope-find-functions-calling-this-function, etc.

Debugging[edit]

Ipdb, ipython debugger[edit]

If you call ipdb, the execution will stop and give a nice ipython-looking prompt. Just add `import ipdb; ipdb.set_trace()`

You can use the following to highlight this line, and not forget it :

; Highlight the call to ipdb
; src http://pedrokroger.com/2010/07/configuring-emacs-as-a-python-ide-2/
(defun annotate-pdb ()
  (interactive)
  (highlight-lines-matching-regexp "import ipdb")
  (highlight-lines-matching-regexp "ipdb.set_trace()"))
(add-hook 'python-mode-hook 'annotate-pdb)

pdb track[edit]

If you use emacs-for-python given above, you can track your source code while debugging with pdbtrack.

A tool to use in a non-emacs terminal would be pdbpp

Other tools[edit]

Pymacs[edit]

Pymacs is an Emacs extension that enables the use of Python alongside with Emacs Lisp.

Pymacs homepage

Auto include import statements[edit]

Ropemacs (see above) is a plugin for performing python refactorings in emacs. It uses rope library and pymacs. It has rope-auto-import, so if you write

   rmtree

and then execute M-x rope-auto-import,

   from shutil import rmtree

is inserted at the top of the file.

Unfortunately Ropemacs can not do non-relative imports, it can only create imports of the "from X import Y" variety (if you type shutil.rmtree it doesn't write import shutil).

Sort import statements[edit]

See the py-isort Melpa package to automatically sort import statements.

See also[edit]

You'll be certainly interested in the following packages (that you will find on ELPA or MELPA):

  • Magit, a git interface. Emacs + git is magic : see magit
  • virtualenvwrapper, to load a virtualenv (so than you can use it with M-x compile) (available through ELPA)
  • helm-pydoc to browse the documentation of installed packages and import one
  • py-isort to sort import statements
  • pungi to integrate jedi, virtualenv and buildout.
  • other ELPA packages

If you're running Emacs 24, check out what is available in ELPA:

M-x list-packages  
and see flymake-pyhon-pyflakes, flymake-shell, abl-mode (a python TDD minor-mode), nose (easy python test-running in emacs), pyregexp, python-magic and more.