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Pymacs merge Dec 9, 2015
completion Fix test_pycomplete for Python 2.7.10 and 3.4.3. Jan 20, 2016
devel Menu docstrings minor-fix Jan 5, 2016
doc Doku updated Feb 10, 2016
extensions Add file extensions/.nosearch Apr 8, 2016
test #7, py-edit-docstring write content back Apr 26, 2016
website #11, which-function-mode sluggish Dec 9, 2015
.travis.yml Some tests fail for unknown reasons at Travis CI Jul 1, 2015
CREDITS py--create-new-shell sets py-exception-buffer incorrectly, lp:1456415 May 19, 2015
EXTENSIONS column-marker.el merged Mar 4, 2012
INSTALL IPYTHON readme added, lp:835151 Mar 7, 2012
INSTALL-INFO-FILES python-info.el patched, lp:1281950 Feb 19, 2014
IPYTHON IPYTHON readme added, lp:835151 Mar 7, 2012
LICENSE LICENSE text GPLv3 added Apr 26, 2011 #11, which-function-mode sluggish Dec 9, 2015
NEWS `py-version' updated Mar 8, 2016 `py-split-window-on-execute-p' renamed `py-split-window-on-execute' Nov 8, 2014 switches focus and does not reuse, lp:1478122, again Aug 13, 2015 Provide Richard Stanton's comment at Mar 16, 2015 py-ert-function-tests.el rewrite Mar 10, 2015 `py-sectionize-region' fixed, python-mode-devs/python-mode#2 Aug 13, 2015 #11, which-function-mode sluggish Dec 9, 2015 Remove redundant Feb 4, 2016 inconvinient-py-shell-switch-buffers-on-execute, lp:1073986 Nov 2, 2012 #11, which-function-mode sluggish Dec 9, 2015 #11, which-function-mode sluggish Dec 9, 2015
python-mode-pkg.el python-mode-pkg.el added Dec 31, 2014
python-mode.el lp:1574731, wrong indent inside string Apr 25, 2016 minor change Feb 4, 2016 #11, which-function-mode sluggish Dec 9, 2015


Put the following into your initialization file:

(setq py-install-directory “PATH/TO/PYTHON-MODE/”) (add-to-list ‘load-path py-install-directory) (require ‘python-mode)

Selecting a Python shell:

Customize default Python shell as `py-shell-name’

`py-shell-name’ might be an installed default executable as shell command `type’ would display, but also a PATH/TO/EXECUTABLE

If different flavours of Python are installed, customize py-python-command - python2 py-python3-command py-ipython-command

py-python-command-args py-python3-command-args py-ipython-command-args

You might run code by another installed (I)Python-version than default.

Normally this would happen if a shebang in buffer specifies it. Shebang precedes default py-shell-name.

In case you will run code by default-shell, ignoring shebang, set `py-force-py-shell-name-p’ to. This might be done also via menu Python/…/Switches

Another way to enforce a different shell is specifiyng a path –interactively C-u prompts for that– or using commands which end in version like `py-execute-statement-python3’ See menu Python/Interpreter/Other/Ignoring Defaults

Invoking an (I)Python interactive shell

Commands related to a specific shell start with it’s name as `ipython-complete’. Open an installed shell by


This calls py-shell with its default arguments


if DEDICATED is set to `t’, shell will get an unique name.

Install a local shell by evaluating

(defun MY-LOCAL-SHELL () (interactive) (py-shell nil DEDICATED PATH-TO-LOCAL-SHELL))

Invoking versioned Python shells in interactive mode:

M-x py-shell RET ==> ”Python” M-x python RET ==> ”Python” M-x ipython RET ==> ”IPython” M-x python3 RET ==> ”Python3

When Path/To/Executable is given C-u python RET ==> ”PTE Python

Prefix conventions

Most python-mode.el commands start with prefix `py-’

`M-x py- TAB’ displays a list of them in completion-buffer. See also commands list delivered in directory doc.

List virtualenv related `M-x virtualenv- TAB’ resp. Pymacs commands `M-x pymacs-’

Execution code

Python code might be processed by an

  • interactive Python shell (DEFAULT)
  • non-interactive Python (`py-fast-process-p’) The latter, while design for large output, seems more reliable - see also

Both processes might run in

  • session, i.e. start from possible previous state (DEFAULT)
  • dedicated, (`py-dedicated-process-p’) run in separate process

There is also

  • python-mode-v5-behavior


Access is provided to a couple of known checkers like Flake8, pep8, pylint Need to be installed for example calling “pip install pep8” from a shell command-line Get flycheck from

Displaying Output

`py-execute-…’-commands arrive in buffer created by `py-shell’. It’s name is composed WRT to Python version used, it’s path etc.

Result of commands ending “-fast” arrives in `py-fast-output-buffer’

Window management

Variables in question:

** py-keep-windows-configuration

Default is nil. When non-nil, it takes precedence over `py-split-window-on-execute’ and `py-switch-buffers-on-execute-p’ settings

Useful, if a pre-designed set of python-shells/buffers should be maintained

** py-split-window-on-execute

When non-nil split windows according to value set.

Default is ‘just-two: when code is send to interpreter, split screen into source-code buffer and current py-shell result. Other buffers will be hidden that way.

When set to `t’, python-mode tries to reuse existing windows and will split only if needed.

With ‘always, results will displayed in a new window.

** py-switch-buffers-on-execute-p

Put focus into the output buffer: this will display buffer in any case


At the end of a word TAB by default calls completion.

Auto-completion should be available via

(require ‘auto-complete-config) (ac-config-default)

or for company:

(autoload ‘company-mode “company” nil t)

There is also a Pymacs based auto-completion mode see

Either use Pymacs and `company-mode’ with `pycomplete.el’ etc. –load stuff from folder completion–

or switch `py-auto-completion-mode-p’ - which relies on `py-shell-complete’, i.e. calls the current Python process.

Extern tools like jedi-server/mode should work too.


Beside common moves like `defun’, `statement’, block called via py-end-of-…, py-beginning-… specific Python-mode edits are delivered:

`py-expression’ and `py-partial-expression’.

Statement below is considered composed of two `py-expression’

a = [‘spam’, ‘eggs’, 100, 1234]


Assigment operator and all inside comments is ignored.

`py-partial-expression’ would match six sections

a = [‘spam’, ‘eggs’, 100, 1234]


When traversing code, `py-partial-expression’ climbs down and up all levels encountered, i.e. at opening `[’ `py-expression’ would return [‘spam’, ‘eggs’, 100, 1234], while one char behind at `” it yields `’spam’,’

  • py-sexp-function, When set, it’s value is called instead of `forward-sexp’, `backward-sexp Choices are py-partial-expression, py-expression, default nil


Customize boolean `py-set-fill-column-p’

If `t’, enables use Python specific `fill-column’ according to

`py-docstring-fill-column’, default is 72

and `py-comment-fill-column, default is 79

Comment- and docstring settings might be disabled by any non-integer value, which means: do not use a different value of `fill-column’ than emacs-wide

Python and IPython

Start IPython shell after loading python-mode via M-x ipython, not from plain shell.

Executing code through IPython should work as with regular Python, also getting completions from. However, with IPython, it feels a demi-second slower.


Start with Emacs -Q from the directory where python-mode.el lives. Open python-mode.el and evaluate it.

Open a file with ending “.py”.

M-x python RET

a regular Python-shell should appear

M-x IPython RET

an IPython-shell should be opened

** pdb doesn’t work at Windows Richard Stanton commented:

Running M-x pdb doesn’t work on my Windows machine, primarily because Windows (at least using the default shell) doesn’t automatically know what to do when you give it a .py command at the command line.

For example, here’s the suggested command when I run pdb on a file c:\projects/


If I accept this, I get an error “Spawning child process: Invalid argument”

A work-around to get it to work is to replace the suggested command with

c:\python27\python -i c:/python27/Lib/ c:/projects/

(note that I not only have to add the python command, but also fully qualify the script file, since otherwise it complains it can’t find the file).

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