ipython.md

The ipython Package

Reference:

• http://ipython.readthedocs.io/en/stable/interactive/tutorial.html
• https://github.com/ipython/ipython

NOTE: The ipython package only works with Python 3.x.

Installation

Once you have learned how to install packages using the pip package manager, you should be able to use it to install a third-party module called ipython, which provides some useful debugging capabilities.

First install ipython, if necessary:

pip install ipython

Usage

Use the ipython package from the command line to enter into an interactive console, or from within a script to debug it using an interactive console.

Command-line Utility

Invoke ipython from the command-line to enter into an alternative console similar to the built-in python console:

ipython
#> Python 3.6.1 (default, Apr  4 2017, 09:40:51)
#> Type 'copyright', 'credits' or 'license' for more information
#> IPython 6.1.0 -- An enhanced Interactive Python. Type '?' for help.
#>
#> In [1]: 2+2
#> Out[1]: 4
#>
#> In [2]:

After you are done, type exit to quit.

Debugging Python Scripts

To drop an interactive break-point onto any line in a Python script, import the package, then insert an embed() statement anywhere you would like the program to pause. Once you run the script, it will stop at the specified break-point to allow further investigation.

from IPython import embed # the capitalization of IPython matters

for i in [1, 2, 3, 4, 5]:
    print(i)
    embed() if i == 4

#> 1
#> 2
#> 3
#> 4
#> Python 3.6.1 (default, Apr  4 2017, 09:40:51)
#> Type 'copyright', 'credits' or 'license' for more information
#> IPython 6.1.0 -- An enhanced Interactive Python. Type '?' for help.
#>
#> In [1]: i
#> Out[1]: 4
#>
#> In [2]:

After you are done, type exit to quit.