Assumed Python 3 throughout docs/intro.

how Django works. This means you should be comfortable going through the

existing tutorials on :doc:`writing your first Django app</intro/tutorial01>`.

In addition, you should have a good understanding of Python itself. But if you

don't, "Dive Into Python" (for `Python 2`__, for `Python 3`__) is a fantastic

(and free) online book for beginning Python programmers.

don't, `Dive Into Python`__ is a fantastic (and free) online book for

beginning Python programmers.

Those of you who are unfamiliar with version control systems and Trac will find

that this tutorial and its links include just enough information to get started.

    to |django-developers| or drop by `#django-dev on irc.freenode.net`__ to

    chat with other Django users who might be able to help.

__ http://diveintopython.net/toc/index.html

__ http://diveintopython3.net/

__ irc://irc.freenode.net/django-dev

    `list of Python resources for non-programmers`_

    If you already know a few other languages and want to get up to speed with

    Python quickly, we recommend "Dive Into Python" (for `Python 2`_, for

    `Python 3`_, also available in a

    `dead-tree version`_). If that's not quite your style, there are quite

    a few other `books about Python`_.

    Python quickly, we recommend `Dive Into Python`_. If that's not quite your

    style, there are many other `books about Python`_.

    .. _python: http://python.org/

    .. _list of Python resources for non-programmers: https://wiki.python.org/moin/BeginnersGuide/NonProgrammers

    .. _Python 2: http://diveintopython.net/

    .. _Python 3: http://diveintopython3.net/

    .. _dead-tree version: http://www.amazon.com/exec/obidos/ASIN/1590593561/ref=nosim/jacobian20

    .. _Dive Into Python: http://diveintopython3.net/

    .. _books about Python: https://wiki.python.org/moin/PythonBooks

.. _sqlite: http://sqlite.org/

Get Python at http://www.python.org. If you're running Linux or Mac OS X, you

probably already have it installed.

Get the latest version of Python at http://www.python.org/download/ or with

your operating system's package manager.

.. admonition:: Django on Jython

You can verify that Python is installed by typing ``python`` from your shell;

you should see something like::

    Python 2.7.3 (default, Jan  2 2013, 13:56:14)

    [GCC 4.7.2] on linux2

    Python 3.3.3 (default, Nov 26 2013, 13:33:18)

    [GCC 4.8.2] on linux

    Type "help", "copyright", "credits" or "license" for more information.

    >>>

.. _object-relational mapper: http://en.wikipedia.org/wiki/Object-relational_mapping

The :doc:`data-model syntax </topics/db/models>` offers many rich ways of

representing your models -- so far, it's been solving two years' worth of

representing your models -- so far, it's been solving many years' worth of

database-schema problems. Here's a quick example, which might be saved in

the file ``mysite/news/models.py``::

    class Reporter(models.Model):

        full_name = models.CharField(max_length=70)

        # On Python 3: def __str__(self):

        def __unicode__(self):

        def __str__(self):              # __unicode__ on Python 2

            return self.full_name

    class Article(models.Model):

        content = models.TextField()

        reporter = models.ForeignKey(Reporter)

        # On Python 3: def __str__(self):

        def __unicode__(self):

        def __str__(self):              # __unicode__ on Python 2

            return self.headline

Install it

    # The API follows relationships as far as you need, performing efficient

    # JOINs for you behind the scenes.

    # This finds all articles by a reporter whose name starts with "John".

    >>> Article.objects.filter(reporter__full_name__startswith="John")

    >>> Article.objects.filter(reporter__full_name__startswith='John')

    [<Article: Django is cool>]

    # Change an object by altering its attributes and calling save().

and renders the template with the retrieved data. Here's an example view for

``year_archive`` from above::

    from django.shortcuts import render_to_response

    from django.shortcuts import render

    def year_archive(request, year):

        a_list = Article.objects.filter(pub_date__year=year)

        return render_to_response('news/year_archive.html', {'year': year, 'article_list': a_list})

        context = {'year': year, 'article_list': a_list}

        return render(request, 'news/year_archive.html', context)

This example uses Django's :doc:`template system </topics/templates>`, which has

several powerful features but strives to stay simple enough for non-programmers

Variables are surrounded by double-curly braces. ``{{ article.headline }}``

means "Output the value of the article's headline attribute." But dots aren't

used only for attribute lookup: They also can do dictionary-key lookup, index

used only for attribute lookup. They also can do dictionary-key lookup, index

lookup and function calls.

Note ``{{ article.pub_date|date:"F j, Y" }}`` uses a Unix-style "pipe" (the "|"

:doc:`custom template tags </howto/custom-template-tags>`, which run custom

Python code behind the scenes.

Finally, Django uses the concept of "template inheritance": That's what the

Finally, Django uses the concept of "template inheritance". That's what the

``{% extends "base.html" %}`` does. It means "First load the template called

'base', which has defined a bunch of blocks, and fill the blocks with the

following blocks." In short, that lets you dramatically cut down on redundancy

It also lets you create multiple versions of a site, with different base

templates, while reusing child templates. Django's creators have used this

technique to create strikingly different cell-phone editions of sites -- simply

by creating a new base template.

technique to create strikingly different mobile versions of sites -- simply by

creating a new base template.

Note that you don't have to use Django's template system if you prefer another

system. While Django's template system is particularly well-integrated with

               'License :: OSI Approved :: BSD License', # example license

               'Operating System :: OS Independent',

               'Programming Language :: Python',

               # replace these appropriately if you are using Python 3

               'Programming Language :: Python :: 2',

               'Programming Language :: Python :: 2.7',

               # Replace these appropriately if you are stuck on Python 2.

               'Programming Language :: Python :: 3',

               'Programming Language :: Python :: 3.2',

               'Programming Language :: Python :: 3.3',

               'Topic :: Internet :: WWW/HTTP',

               'Topic :: Internet :: WWW/HTTP :: Dynamic Content',

           ],