***********
Preparation
***********

We'll use Django Version |djangoversion|. To get started we need to do
a little preparation.

.. index:: Install Python

Python
======

Django is written completely in `Python <https://www.python.org/>`_.
Therefore Python needs to be installed first.

.. note::

    Django |djangoversion| supports Python from version 2.7. If you have an
    older version of Python, you should update it. Django supports Python 3
    since version 1.5.

You can find out which version of Python you're running by using the
command line option :option:`--version`:

.. command-output:: python --version

.. note::

    If you are using Python 3 please make sure you have Python 3.3.2 or
    greater installed. Otherwise there will be problems.

    Also consider adding the following future-import on top of every
    Python file you are going to edit to ensure Python 2 and 3
    compatibility:

    ::

        from __future__ import unicode_literals

    This way all regular strings will be unicode string literals.

    If you want to learn more read the :djangodocs:`Python 3
    <topics/python3/>` part of the Django documentation.

If you've already got the right version of Python installed, you can
skip ahead to :ref:`Python Package Managers <python-package-manager>`.

Linux
-----

Many Linux distributions come with Python already installed. If you
haven't got a version of Python installed, you can normally use your
package manager to download and install it.

Alternatively, you can get the `Python Sources
<https://www.python.org/downloads/>`_ from the website and compile it
yourself.

Mac OS X
--------

Python comes pre-installed on Mac OS X. You can however use `Homebrew
<http://brew.sh/>`_ to install your own copy of Python.

Windows
-------

Download the `Installer <https://www.python.org/downloads/>`_ from the Python
Website and install it.

So that Python works under Windows as expected, you need to change the
environment variable :envvar:`%PATH%`. In the examples, we'll assume
that your Python is installed in :file:`C:\\Python27\\`.

Windows 7
^^^^^^^^^

#. :menuselection:`Start`, then right click on :menuselection:`Computer`
#. Now click the context menu option :guilabel:`Properties`
#. Next, in the window that just opened, click on the
   :guilabel:`Advanced System Settings`
#. A further window will open, click the
   :guilabel:`Environment Variables`
#. Under `System Variables`, select the :option:`PATH`
#. Now click on :guilabel:`Edit` and add the required directory:
   ``;C:\Python27\;C:\Python27\Scripts;``. (The semi-colon at the
   beginning is required!)
#. Now close the windows :guilabel:`Environment Variables` and
   :guilabel:`System Properties` by clicking on `OK`.

Windows XP
^^^^^^^^^^

#. :menuselection:`Start --> Control Panel --> System --> Advanced`
#. Click on the :guilabel:`Environment Variables`, then a new window
   will open. Under "System Variables" select :option:`Path`
#. Now click on :guilabel:`Edit` and add the required directory:
   ``;C:\Python27\;C:\Python27\Scripts;``. (The semi-colon at the
   beginning is required!)
#. Now close the windows :guilabel:`Environment Variables` and
   :guilabel:`System Properties` by clicking on `OK`.

.. index:: Install Python Package Manager
.. _python-package-manager:

Python Package Manager
======================

.. index:: pip

Python has its own :pythondocs:`package system <installing/>` to manage
distribution and installation of Python packages. Because we will need to
install several packages, we must first make sure the package manager `pip
<https://pip.pypa.io/en/stable/>`_ is installed. :program:`pip` was originally
written as an improvement of :program:`easy_install`.

To decide which installation procedure is right for you check again your Python version:

.. command-output:: python --version

Python 3.4 and Python 2.7.9
---------------------------

If you have Python 3.4 or Python 2.7.9 (or newer) installed you can use
:pythondocs:`ensurepip <library/ensurepip.html>` to install or upgrade :program:`pip`:

::

    $ python -m ensurepip --upgrade

If your Python version is too old you will simply see an error message like that:

::

    $ python -m ensurepip --upgrade
    /usr/bin/python: No module named ensurepip

Python 3.3 and Python 2
-----------------------

If you have Python 3.3 or Python 2 with a version lower than 2.7.9 installed,
your Python installation does not contain the module `ensurepip`. In this case
:program:`pip` can be installed with the help from a `bootstrap script
<https://bootstrap.pypa.io/get-pip.py>`_. If :program:`curl` is installed, you
can use it to download :program:`pip` at the command line. Otherwise just use
the browser.

::

    $ curl -O https://bootstrap.pypa.io/get-pip.py

When the bootstrap script has been downloaded execute it to install
:program:`pip`:

::

    $ python get-pip.py

.. note::

    Under Linux and Mac OS X root privileges may be required. In this case
    use:

    ::

       $ sudo python get-pip.py

.. note::

    If you have problems running :file:`get-pip.py` because of the
    configuration of your internet connection please have a look the `pip
    installation documentation <https://pip.pypa.io/en/stable/installing.html
    #install-pip>`_.

You can delete the bootstrap script when the installation has been finished.

Test pip
--------

After a successful upgrade or installation, you can test :program:`pip` as
follows:

.. command-output:: pip --version