litelatur

1. Python - ArchWiki
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https://wiki.archlinux.org/index.php/Python
Python
From ArchWiki
Python (http://www.python.org) "is a remarkably powerful dynamic
programming language that is used in a wide variety of application domains.
Python is often compared to Tcl, Perl, Ruby, Scheme or Java."
Related articles
Python Package
Guidelines
mod_python
Contents
Python VirtualEnv
1 Installation
1.1 Python 3
1.2 Python 2
2 Dealing with version problem in build scripts
3 Integrated Development Environments
3.1 Eclipse
3.2 Eric
3.3 IEP
3.4 Ninja
3.5 Spyder
4 Getting easy_install
5 Getting completion in Python shell
6 Widget bindings
7 Old versions
8 More Resources
9 For Fun
Installation
There are currently two versions of Python: Python 3 (which is the default) and the older Python 2.
Python 3
Python 3 is the latest version of the language, and is incompatible with Python 2. The language is mostly
the same, but many details, especially how built-in objects like dictionaries and strings work, have changed
considerably, and a lot of deprecated features have finally been removed. Also, the standard library has been
reorganized in a few prominent places. For an overview of the differences, visit Python2orPython3
(http://wiki.python.org/moin/Python2orPython3) and their relevant chapter (http://getpython3.com
/diveintopython3/porting-code-to-python-3-with-2to3.html) in Dive into Python 3.
To install the latest version of Python 3, install the python (https://www.archlinux.org/packages
/?name=python) package from the official repositories.
If you would like to build the latest RC/betas from source, visit Python Downloads (http://www.python.org
/download/). The Arch User Repository also contains good PKGBUILDs. If you do decide to build the RC,
note that the binary (by default) installs to /usr/local/bin/python3.x .
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2. Python - ArchWiki
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https://wiki.archlinux.org/index.php/Python
Python 2
To install the latest version of Python 2, install the python2 (https://www.archlinux.org/packages
/?name=python2) package from the official repositories.
Python 2 will happily run alongside Python 3. You need to specify python2 in order to run this version.
Any program requiring Python 2 needs to point to /usr/bin/python2 , instead of /usr/bin/python ,
which points to Python 3.
To do so, open the program or script in a text editor and change the first line.
The line will show one of the following:
#!/usr/bin/env python
or
#!/usr/bin/python
In both cases, just change python to python2 and the program will then use Python 2 instead of Python 3.
Another way to force the use of python2 without altering the scripts is to call it explicitely with python2, i.e.
python2 myScript.py
Finally, you may not be able to control the script calls, but there is a way to trick the environment. It only
works if the scripts use #!/usr/bin/env python , it won't work with #!/usr/bin/python . This trick
relies on env searching for the first corresponding entry in the PATH variable. First create a dummy folder.
$ mkdir ~/bin
Then add a symlink 'python' to python2 and the config scripts in it.
$ ln -s /usr/bin/python2 ~/bin/python
$ ln -s /usr/bin/python2-config ~/bin/python-config
Finally put the new folder at the beginning of your PATH variable.
$ export PATH=~/bin:$PATH
Note that this change is not permanent and is only active in the current terminal session. To check which
python interpreter is being used by env , use the following command:
$ which python
A similar approach in tricking the environment, which also relies on #!/usr/bin/env python to be called
by the script in question, is to use a Virtualenv. When a Virtualenv is activated, the Python executable
pointed to by $PATH will be the one the Virtualenv was installed with. Therefore, if the Virtualenv is
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3. Python - ArchWiki
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https://wiki.archlinux.org/index.php/Python
installed with Python 2, python will refer to Python 2. To start, install python2-virtualenv
(https://www.archlinux.org/packages/?name=python2-virtualenv).
# pacman -S python2-virtualenv
Then create the Virtualenv.
$ virtualenv2 venv # Creates a directory, venv/, containing the Virtualenv
Activate the Virtualenv, which will update $PATH to point at Python 2. Note that this activation is only
active for the current terminal session.
$ source venv/bin/activate
The desired script should then run using Python 2.
Dealing with version problem in build scripts
Many projects' build scripts assume python to be Python 2, and that would eventually result in an error typically complaining that print 'foo' is invalid syntax. Luckily, many of them call python in the
$PATH instead of hardcoding #!/usr/bin/python in the shebang line, and the Python scripts are all
contained within the project tree. So, instead of modifying the build scripts manually, there is an easy
workaround. Just create /usr/local/bin/python with content like this:
/usr/local/bin/python
#!/bin/bash
script=`readlink -f -- "$1"`
case "$script" in (/path/to/project1/*|/path/to/project2/*|/path/to/project3*)
exec python2 "$@"
;;
esac
script=`readlink -f -- "$2"`
case "$script" in (/path/to/project1/*|/path/to/project2/*|/path/to/project3*)
exec python2 "$@"
;;
esac
exec python3 "$@"
Where /path/to/project1/*|/path/to/project2/*|/path/to/project3* is a list of patterns separated
by | matching all project trees.
Don't forget to make it executable:
# chmod +x /usr/local/bin/python
Afterwards scripts within the specified project trees will be run with Python 2.
Integrated Development Environments
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4. Python - ArchWiki
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https://wiki.archlinux.org/index.php/Python
There are some IDEs for Python available in the official repositories.
Eclipse
Eclipse supports both Python 2.x and 3.x series by using the PyDev extension.
Eric
For the latest Python 3 compatible version, install the eric (https://www.archlinux.org/packages
/?name=eric) package.
Version 4 of Eric is Python 2 compatible and can be installed with the eric4
(https://www.archlinux.org/packages/?name=eric4) package.
These IDEs can also handle Ruby.
IEP
IEP is an interactive (e.g. MATLAB) python IDE with basic debugging capabilities and is especially suitable
for scientific computing. It is provided by the package iep (https://aur.archlinux.org/packages
/iep/).
Ninja
The Ninja IDE is provided by the package ninja-ide (https://www.archlinux.org/packages
/?name=ninja-ide).
Spyder
Spyder (previously known as Pydee) is a powerful interactive development environment for the Python
language with advanced editing, interactive testing, debugging and introspection features. It focuses on
scientific computations, providing a matlab-like environment. It can be installed with the package spyder
(https://aur.archlinux.org/packages/spyder/)
Getting easy_install
The easy_install tool is available in the package python-setuptools (https://www.archlinux.org
/packages/?name=python-setuptools).
Getting completion in Python shell
Copy this into Python's interactive shell
/usr/bin/python
import rlcompleter
import readline
readline.parse_and_bind("tab: complete")
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5. Python - ArchWiki
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https://wiki.archlinux.org/index.php/Python
Source (http://algorithmicallyrandom.blogspot.com.es/2009/09/tab-completion-in-python-shell-how-to.html)
Widget bindings
The following widget toolkit bindings are available:
TkInter — Tk bindings
http://wiki.python.org/moin/TkInter || standard module
pyQt — Qt bindings
http://www.riverbankcomputing.co.uk/software/pyqt/intro || python2-pyqt4
(https://www.archlinux.org/packages/?name=python2-pyqt4) python2-pyqt5
(https://www.archlinux.org/packages/?name=python2-pyqt5) python-pyqt4
(https://www.archlinux.org/packages/?name=python-pyqt4) python-pyqt5
(https://www.archlinux.org/packages/?name=python-pyqt5)
pySide — Qt bindings
http://www.pyside.org/ || python2-pyside (https://aur.archlinux.org/packages/python2pyside/) python-pyside (https://aur.archlinux.org/packages/python-pyside/)
pyGTK — GTK+ 2 bindings
http://www.pygtk.org/ || pygtk (https://www.archlinux.org/packages/?name=pygtk)
PyGObject — GTK+ 2/3 bindings via GObject Introspection
https://wiki.gnome.org/PyGObject/ || python2-gobject2 (https://www.archlinux.org/packages
/?name=python2-gobject2) python2-gobject (https://www.archlinux.org/packages
/?name=python2-gobject) python-gobject2 (https://www.archlinux.org/packages
/?name=python-gobject2) python-gobject (https://www.archlinux.org/packages
/?name=python-gobject)
wxPython — wxWidgets bindings
http://wxpython.org/ || wxpython (https://www.archlinux.org/packages/?name=wxpython)
To use these with Python, you may need to install the associated widget kits.
Old versions
Old versions of Python are available via the AUR and may be useful for historical curiosity, old applications
that don't run on current versions, or for testing Python programs intended to run on a distribution that
comes with an older version (eg, RHEL 5.x has Python 2.4, or Ubuntu 12.04 has Python 3.1):
python15 (https://aur.archlinux.org/packages/python15/):
python16
python24
python25
python26
python30
Python 1.5.2
(https://aur.archlinux.org/packages/python16/): Python 1.6.1
(https://aur.archlinux.org/packages/python24/): Python 2.4.6
(https://aur.archlinux.org/packages/python25/): Python 2.5.6
(https://aur.archlinux.org/packages/python26/): Python 2.6.8
(https://aur.archlinux.org/packages/python30/): Python 3.0.1
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6. Python - ArchWiki
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https://wiki.archlinux.org/index.php/Python
python31 (https://aur.archlinux.org/packages/python31/):
Python 3.1.5
python32 (https://aur.archlinux.org/packages/python32/): Python 3.2.3
As of November 2012, Python upstream only supports Python 2.6, 2.7, 3.1, 3.2, and 3.3 for security fixes.
Using older versions for Internet-facing applications or untrusted code may be dangerous and is not
recommended.
Extra modules/libraries for old versions of Python may be found on the AUR by searching for
python(version without decimal), eg searching for "python26" for 2.6 modules.
More Resources
Learning Python (http://shop.oreilly.com/product/9780596158071.do) is one of the most
comprehensive, up to date, and well-written books on Python available today.
Dive Into Python (http://www.diveintopython.net/) is an excellent (free) resource, but perhaps for
more advanced readers and has been updated for Python 3 (http://diveintopython3.ep.io/).
A Byte of Python (http://www.swaroopch.com/notes/Python) is a book suitable for users new to
Python (and scripting in general).
Learn Python The Hard Way (http://learnpythonthehardway.org) the best intro to programming.
facts.learnpython.org (http://facts.learnpython.org) nice site to learn python.
Crash into Python (http://stephensugden.com/crash_into_python/) Also known as Python for
Programmers with 3 Hours, this guide gives experienced developers from other languages a crash
course on Python.
Beginning Game Development with Python and Pygame: From Novice to Professional
(http://www.apress.com/book/view/9781590598726) for games
For Fun
Try the following snippets from Python's interactive shell:
>>> import this
>>> from __future__ import braces
>>> import antigravity
Retrieved from "https://wiki.archlinux.org/index.php?title=Python&oldid=294398"
Category: Programming language
This page was last modified on 25 January 2014, at 21:30.
Content is available under GNU Free Documentation License 1.3 or later unless otherwise noted.
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