How to save a Python interactive session?

Question

I find myself frequently using Python's interpreter to work with databases, files, etc -- basically a lot of manual formatting of semi-structured data. I don't properly save and clean up the useful bits as often as I would like. Is there a way to save my input into the shell (db connections, variable assignments, little for loops and bits of logic) -- some history of the interactive session? If I use something like script I get too much stdout noise. I don't really need to pickle all the objects -- though if there is a solution that does that, it would be OK. Ideally I would just be left with a script that ran as the one I created interactively, and I could just delete the bits I didn't need. Is there a package that does this, or a DIY approach?

UPDATE: I am really amazed at the quality and usefulness of these packages. For those with a similar itch:

• IPython -- should have been using this for ages, kind of what I had in mind
• reinteract -- very impressive, I want to learn more about visualization and this seems like it will shine there. Sort of a gtk/gnome desktop app that renders graphs inline. Imagine a hybrid shell + graphing calculator + mini eclipse. Source distribution here: http://www.reinteract.org/trac/wiki/GettingIt . Built fine on Ubuntu, integrates into gnome desktop, Windows and Mac installers too.
• bpython -- extremely cool, lots of nice features, autocomplete(!), rewind, one keystroke save to file, indentation, well done. Python source distribution, pulled a couple of dependencies from sourceforge.

I am converted, these really fill a need between interpreter and editor.

Answer 1

Some comments were asking how to save all of the IPython inputs at once. For %save magic in IPython, you can save all of the commands programmatically as shown below, to avoid the prompt message and also to avoid specifying the input numbers. currentLine = len(In)-1 %save -f my_session 1-$currentLine

The -f option is used for forcing file replacement and the len(IN)-1 shows the current input prompt in IPython, allowing you to save the whole session programmatically.

Answer 2

There is a way to do it. Store the file in ~/.pystartup...

# Add auto-completion and a stored history file of commands to your Python
# interactive interpreter. Requires Python 2.0+, readline. Autocomplete is
# bound to the Esc key by default (you can change it - see readline docs).
#
# Store the file in ~/.pystartup, and set an environment variable to point
# to it:  "export PYTHONSTARTUP=/home/user/.pystartup" in bash.
#
# Note that PYTHONSTARTUP does *not* expand "~", so you have to put in the
# full path to your home directory.

import atexit
import os
import readline
import rlcompleter

historyPath = os.path.expanduser("~/.pyhistory")

def save_history(historyPath=historyPath):
    import readline
    readline.write_history_file(historyPath)

if os.path.exists(historyPath):
    readline.read_history_file(historyPath)

atexit.register(save_history)
del os, atexit, readline, rlcompleter, save_history, historyPath

and then set the environment variable PYTHONSTARTUP in your shell (e.g. in ~/.bashrc):

export PYTHONSTARTUP=$HOME/.pystartup

You can also add this to get autocomplete for free:

readline.parse_and_bind('tab: complete')

Please note that this will only work on *nix systems. As readline is only available in Unix platform.

Answer 3

Also, reinteract gives you a notebook-like interface to a Python session.

Answer 4

If you are using IPython you can save to a file all your previous commands using the magic function %history with the -f parameter, p.e:

%history -f /tmp/history.py

Answer 5

There is %history magic for printing and saving the input history (and optionally the output).

To store your current session to a file named my_history.py:

>>> %hist -f my_history.py

History IPython stores both the commands you enter, and the results it produces. You can easily go through previous commands with the up- and down-arrow keys, or access your history in more sophisticated ways.

You can use the %history magic function to examine past input and output. Input history from previous sessions is saved in a database, and IPython can be configured to save output history.

Several other magic functions can use your input history, including %edit, %rerun, %recall, %macro, %save and %pastebin. You can use a standard format to refer to lines:

%pastebin 3 18-20 ~1/1-5

This will take line 3 and lines 18 to 20 from the current session, and lines 1-5 from the previous session.

See %history? for the Docstring and more examples.

Also, be sure to explore the capabilities of %store magic for lightweight persistence of variables in IPython.

Stores variables, aliases and macros in IPython’s database.

d = {'a': 1, 'b': 2}
%store d  # stores the variable
del d

%store -r d  # Refresh the variable from IPython's database.
>>> d
{'a': 1, 'b': 2}

To autorestore stored variables on startup, specifyc.StoreMagic.autorestore = True in ipython_config.py.

Answer 6

Just putting another suggesting in the bowl: Spyder

It has History log and Variable explorer. If you have worked with MatLab, then you'll see the similarities.