Python: Debugging pdb, Ipython Magics

Python Debugging

pdb is a standard python debuger and to invoke it we can call brakpoint() in scripts or use %pdb magic in iPython. Documentation

In pdb pythons standard debugger, help command directs you further. Some shortcuts are n next line, s step into, c for continue. You can do anything w.r.t ipython shell.

More info: https://realpython.com/python-debugging-pdb/

Some of other tools/ways are:

• from IPython import embed; embed()
• from import ipdb; ipdb.set_trace()

IPython trics:

All and more about useful ipython %magic and debugging can be found here:

Great reference: https://jakevdp.github.io/PythonDataScienceHandbook/index.html

• %lsmagic to list all available magic commands
• %<magic>?: to understand the magic command more
• Debugging:
  • %debug will bring pdb from when exception was raised and hence you can check all variables
  • %xmode Plain, %xmode Verbose
  • %pdb on, %pdb off, %pdb 1, %pdb 0
  • To bring up pdb whenever exception is raised set %pdb on.
• Profiling:
  • %time: Time the execution of a single statement
  • %timeit: Time repeated execution of a single statement for more accuracy
  • %prun: Run code with the profiler
  • %lprun: Run code with the line-by-line profiler
  • %memit: Measure the memory use of a single statement
  • %mprun: Run code with the line-by-line memory profiler
• Listing variables:
  • dir()
  • globals()
  • locals()