Select Notebook Name When Renaming a Notebook

The default notebook name is Untitled. It's unlikely you want to keep this name or part of it when naming your notebook. Instead, IPython will select the text in the input field so the user can easily type over the name and change it.

clear_output changes

• There is no longer a 500ms delay when calling clear_output.
• The ability to clear stderr and stdout individually was removed.
• A new wait flag that prevents clear_output from being executed until new output is available. This eliminates animation flickering by allowing the user to double buffer the output.
• The output div height is remembered when the wait=True flag is used.

Extending Configurable Containers

Some configurable traits are containers (list, dict, set) Config objects now support calling extend, update, insert, etc. on traits in config files, which will ultimately result in calling those methods on the original object.

The effect being that you can now add to containers without having to copy/paste the initial value:

c = get_config()
c.InlineBackend.rc.update({ 'figure.figsize' : (6, 4) })

Single codebase Python 3 support

IPython previously supported Python 3 by running 2to3 during setup. We have now switched to a single codebase which runs natively on Python 2.7 and 3.3.

For notes on how to maintain this, see :doc:`/development/pycompat`.

changes to hidden namespace on startup

Previously, all names declared in code run at startup (startup files, ipython -i script.py, etc.) were added to the hidden namespace, which hides the names from tools like %whos. There are two changes to this behavior:

1. Scripts run on the command-line ipython -i script.py``now behave the same as if they were passed to ``%run, so their variables are never hidden.
2. A boolean config flag InteractiveShellApp.hide_initial_ns has been added to optionally disable the hidden behavior altogether. The default behavior is unchanged.

Using dill to expand serialization support

adds :func:`~IPython.utils.pickleutil.use_dill` for allowing dill to extend serialization support in :mod:`IPython.parallel` (closures, etc.). Also adds :meth:`DirectView.use_dill` convenience method for enabling dill locally and on all engines with one call.

New IPython Console Lexer

The IPython console lexer has been rewritten and now supports tracebacks and customized input/output prompts. An entire suite of lexers is now available at :mod:`IPython.nbconvert.utils.lexers`. These include:

IPythonLexer & IPython3Lexer

Lexers for pure IPython (python + magic/shell commands)

IPythonPartialTracebackLexer & IPythonTracebackLexer

Supports 2.x and 3.x via the keyword python3. The partial traceback lexer reads everything but the Python code appearing in a traceback. The full lexer combines the partial lexer with an IPython lexer.

IPythonConsoleLexer

A lexer for IPython console sessions, with support for tracebacks. Supports 2.x and 3.x via the keyword python3.

IPyLexer

A friendly lexer which examines the first line of text and from it, decides whether to use an IPython lexer or an IPython console lexer. Supports 2.x and 3.x via the keyword python3.

Previously, the :class:`IPythonConsoleLexer` class was available at :mod:`IPython.sphinxext.ipython_console_hightlight`. It was inserted into Pygments' list of available lexers under the name ipython. It should be mentioned that this name is inaccurate, since an IPython console session is not the same as IPython code (which itself is a superset of the Python language).

Now, the Sphinx extension inserts two console lexers into Pygments' list of available lexers. Both are IPyLexer instances under the names: ipython and ipython3. Although the names can be confusing (as mentioned above), their continued use is, in part, to maintain backwards compatibility and to aid typical usage. If a project needs to make Pygments aware of more than just the IPyLexer class, then one should not make the IPyLexer class available under the name ipython and use ipy or some other non-conflicting value.

Code blocks such as:

.. code-block:: ipython

    In [1]: 2**2
    Out[1]: 4

will continue to work as before, but now, they will also properly highlight tracebacks. For pure IPython code, the same lexer will also work:

.. code-block:: ipython

    x = ''.join(map(str, range(10)))
    !echo $x

Since the first line of the block did not begin with a standard IPython console prompt, the entire block is assumed to consist of IPython code instead.

DisplayFormatter changes

There was no official way to query or remove callbacks in the Formatter API. To remedy this, the following methods are added to :class:`BaseFormatter`:

• lookup(instance) - return appropriate callback or a given object
• lookup_by_type(type_or_str) - return appropriate callback for a given type or 'mod.name' type string
• pop(type_or_str) - remove a type (by type or string). Pass a second argument to avoid KeyError (like dict).

All of the above methods raise a KeyError if no match is found.

And the following methods are changed:

• for_type(type_or_str) - behaves the same as before, only adding support for 'mod.name' type strings in addition to plain types. This removes the need for for_type_by_name(), but it remains for backward compatibility.

Notebook Widgets

Available in the new IPython.html.widgets namespace, widgets provide an easy way for IPython notebook users to display GUI controls in the IPython notebook. IPython comes with bundle of built-in widgets and also the ability for users to define their own widgets. A widget is displayed in the front-end using using a view. For example, a FloatRangeWidget can be displayed using a FloatSliderView (which is the default if no view is specified when displaying the widget). IPython also comes with a bundle of views and the ability for the user to define custom views. One widget can be displayed multiple times, in on or more cells, using one or more views. All views will automatically remain in sync with the widget which is accessible in the back-end.

The widget layer provides an MVC-like architecture on top of the comm layer. It's useful for widgets that can be expressed via a list of properties. Widgets work by synchronizing IPython traitlet models in the back-end with backbone models in the front-end. The widget layer automatically handles

• delta compression (only sending the state information that has changed)
• wiring the message callbacks to the correct cells automatically
• inter-view synchronization (handled by backbone)
• message throttling (to avoid flooding the kernel)
• parent/child relationships between views (which one can override to specify custom parent/child relationships)
• ability to manipulate the widget view's DOM from python using CSS, $().addClass, and $().removeClass methods

Signing Notebooks

To prevent untrusted code from executing on users' behalf when notebooks open, we have added a signature to the notebook, stored in metadata.

For more information, see :ref:`signing_notebooks`.

Other changes

• %%capture cell magic now captures the rich display output, not just stdout/stderr
• In notebook, Showing tooltip on tab has been disables to avoid conflict with completion, Shift-Tab could still be used to invoke tooltip when inside function signature and/or on selection.
• object_info_request as been replaced by object_info for consistency in the javascript API. object_info as a simpler interface to register callback that is incompatible with object_info_request.
• Previous versions of IPython on Linux would use the XDG config directory, creating :file:`~/.config/ipython` by default. We have decided to go back to :file:`~/.ipython` for consistency among systems. IPython will issue a warning if it finds the XDG location, and will move it to the new location if there isn't already a directory there.
• Equations, images and tables are now centered in Markdown cells.
• Multiline equations are now centered in output areas; single line equations remain left justified.
• IPython config objects can be loaded from and serialized to JSON. JSON config file have the same base name as their .py counterpart, and will be loaded with higher priority if found.
• bash completion updated with support for all ipython subcommands and flags, including nbconvert
• ipython history trim: added --keep=<N> as an alias for the more verbose --HistoryTrim.keep=<N>
• new ipython history clear subcommand, which is the same as the newly supported ipython history trim --keep=0
• You can now run notebooks in an interactive session via %run notebook.ipynb.
• Print preview is back in the notebook menus, along with options to download the open notebook in various formats. This is powered by nbconvert.
• :exc:`~IPython.nbconvert.utils.pandoc.PandocMissing` exceptions will be raised if Pandoc is unavailable, and warnings will be printed if the version found is too old. The recommended Pandoc version for use with nbconvert is 1.12.1.
• The InlineBackend.figure_format flag now supports JPEG output if PIL/Pillow is available.
• Input transformers (see :doc:`/config/inputtransforms`) may now raise :exc:`SyntaxError` if they determine that input is invalid. The input transformation machinery in IPython will handle displaying the exception to the user and resetting state.

Backwards incompatible changes

• Python 2.6 and 3.2 are no longer supported: the minimum required Python versions are now 2.7 and 3.3.

• The Transformer classes have been renamed to Preprocessor in nbconvert and their call methods for them have been renamed to preprocess.

• The call methods of nbconvert post-processsors have been renamed to postprocess.

• The module IPython.core.fakemodule has been removed.

• The alias system has been reimplemented to use magic functions. There should be little visible difference while automagics are enabled, as they are by default, but parts of the :class:`~IPython.core.alias.AliasManager` API have been removed.

• We fixed an issue with switching between matplotlib inline and GUI backends, but the fix requires matplotlib 1.1 or newer. So from now on, we consider matplotlib 1.1 to be the minimally supported version for IPython. Older versions for the most part will work, but we make no guarantees about it.

• The :command:`pycolor` command has been removed. We recommend the much more capable :command:`pygmentize` command from the Pygments project. If you need to keep the exact output of :command:`pycolor`, you can still use python -m IPython.utils.PyColorize foo.py.

• :mod:`IPython.lib.irunner` and its command-line entry point have been removed. It had fallen out of use long ago.

• The input_prefilter hook has been removed, as it was never actually used by the code. The input transformer system offers much more powerful APIs to work with input code. See :doc:`/config/inputtransforms` for details.

• :class:`IPython.core.inputsplitter.IPythonInputSplitter` no longer has a method source_raw_reset(), but gains :meth:`~IPython.core.inputsplitter.IPythonInputSplitter.raw_reset` instead. Use of source_raw_reset can be replaced with:

  raw = isp.source_raw
  transformed = isp.source_reset()