How can I get tab-completion in the interactive Python interpreter?

Question

I often use Python 3000's interactive interpreter, but it's missing the convenience of tab-completion I'm used to from ipython, which isn't available for Python 3.x.

How do I enable tab completion in all of them, 2.6 and 3.x?

Solution

First, create a new file called .pythonstartup.py in your home directory. Put the following script in it:

try:
    import readline
except ImportError:
    print("Module readline not available.")
else:
    import rlcompleter
    readline.parse_and_bind("tab: complete")

The parentheses around the string ensure that it works with both Python 2 and Python 3.

Every time the interactive interpreter is started, it executes a script defined in $PYTHONSTARTUP, if there is one. To set it to execute the above script, type

export PYTHONSTARTUP="~/.pythonstartup.py"

You should write this line to your .bashrc or .bash_profile file, so that it's automatically executed when a new shell is started.

Comments

[Pithikos]

NOTICE: This won't work if you start the terminal and then change directory. If you want this method to work no matter the directory you are, you should use the full path like export PYTHONSTARTUP="/home/user/.pythonstartup.py"

[Mikael Fremling]

Your can make the export a bit more tolerant by having export PYTHONSTARTUP=~/.pythonstartup.py

[chris]

This doesn't work if you start a file in interactive mode, e.g. python -i main.py. Any way to do that?