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.. _tips:
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=====================
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IPython Tips & Tricks
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=====================
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The `IPython cookbook <http://ipython.scipy.org/moin/Cookbook>`_ details more
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things you can do with IPython.
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.. This is not in the current version:
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Embed IPython in your programs
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------------------------------
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A few lines of code are enough to load a complete IPython inside your own
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programs, giving you the ability to work with your data interactively after
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automatic processing has been completed. See :ref:`the embedding section <embedding>`.
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Run doctests
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------------
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Run your doctests from within IPython for development and debugging. The
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special %doctest_mode command toggles a mode where the prompt, output and
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exceptions display matches as closely as possible that of the default Python
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interpreter. In addition, this mode allows you to directly paste in code that
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contains leading '>>>' prompts, even if they have extra leading whitespace
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(as is common in doctest files). This combined with the ``%history -t`` call
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to see your translated history allows for an easy doctest workflow, where you
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can go from doctest to interactive execution to pasting into valid Python code
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as needed.
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Use IPython to present interactive demos
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----------------------------------------
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Use the :class:`IPython.lib.demo.Demo` class to load any Python script as an interactive
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demo. With a minimal amount of simple markup, you can control the execution of
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the script, stopping as needed. See :ref:`here <interactive_demos>` for more.
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Suppress output
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---------------
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Put a ';' at the end of a line to suppress the printing of output. This is
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useful when doing calculations which generate long output you are not
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interested in seeing.
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Lightweight 'version control'
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-----------------------------
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When you call ``%edit`` with no arguments, IPython opens an empty editor
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with a temporary file, and it returns the contents of your editing
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session as a string variable. Thanks to IPython's output caching
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mechanism, this is automatically stored::
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In [1]: %edit
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IPython will make a temporary file named: /tmp/ipython_edit_yR-HCN.py
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Editing... done. Executing edited code...
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hello - this is a temporary file
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Out[1]: "print 'hello - this is a temporary file'\n"
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Now, if you call ``%edit -p``, IPython tries to open an editor with the
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same data as the last time you used %edit. So if you haven't used %edit
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in the meantime, this same contents will reopen; however, it will be
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done in a new file. This means that if you make changes and you later
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want to find an old version, you can always retrieve it by using its
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output number, via '%edit _NN', where NN is the number of the output
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prompt.
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Continuing with the example above, this should illustrate this idea::
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In [2]: edit -p
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IPython will make a temporary file named: /tmp/ipython_edit_nA09Qk.py
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Editing... done. Executing edited code...
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hello - now I made some changes
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Out[2]: "print 'hello - now I made some changes'\n"
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In [3]: edit _1
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IPython will make a temporary file named: /tmp/ipython_edit_gy6-zD.py
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Editing... done. Executing edited code...
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hello - this is a temporary file
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IPython version control at work :)
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Out[3]: "print 'hello - this is a temporary file'\nprint 'IPython version control at work :)'\n"
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This section was written after a contribution by Alexander Belchenko on
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the IPython user list.
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.. The section below needs to be updated for the new config system.
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.. Effective logging
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-----------------
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.. A very useful suggestion sent in by Robert Kern follows:
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.. I recently happened on a nifty way to keep tidy per-project log files. I
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made a profile for my project (which is called "parkfield")::
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include ipythonrc
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# cancel earlier logfile invocation:
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logfile ''
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execute import time
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execute __cmd = '/Users/kern/research/logfiles/parkfield-%s.log rotate'
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execute __IP.magic_logstart(__cmd % time.strftime('%Y-%m-%d'))
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.. I also added a shell alias for convenience::
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alias parkfield="ipython --pylab profile=parkfield"
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.. Now I have a nice little directory with everything I ever type in,
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organized by project and date.
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