Debugging code with IPython

Debugging is an integral part of software development and interactive computing. A widespread debugging technique consists of placing the print() functions in various places in the code. Who hasn't done this? It is probably the simplest solution, but it is certainly not the most efficient (it is the poor man's debugger).

IPython is perfectly adapted for debugging, and the integrated debugger is quite easy to use (actually, IPython merely offers a nice interface to the native Python debugger pdb). In particular, tab completion works in the IPython debugger. This recipe describes how to debug code with IPython.

How to do it...

There are two not-mutually exclusive ways of debugging code in Python. In the post-mortem mode, the debugger steps into the code as soon as an exception is raised, so that we can investigate what caused it. In the step-by-step mode, we can stop the interpreter at a breakpoint and resume its execution step by step. This process allows us to check...