Python has a debugger called pdb. Let's find out how can we use it instead of Pycharm.

To The Point

Calling PDB Stack Trace

There is a PDB class that enables python debugging without additional python packages.

To use it, call stack-trace like that:

import pdb

pdb.set_trace()

The line in which you will put pdb.set_trace() is the one from which pdb will invoke stack-trace.

There is also a way in which you will start function without setting particular line at which stack-trace should start:

import pdb
import yourmodulename
pdb.run('yourmodulename.yourfunction()')

PDB stack trace is interactive - in a similar way as in Pycharm.

You can use commands in pdb to analyze stack-trace.

You can either write one letter of the command or full name of command - but some of the commands needs to be written in a full-length.

The most used commands:

u(p) - moves current stack-trace frame up
d(own) - moves current stack-trace frame down
b(reak) [([filename:]lineno | function) [, condition]]
- without argument lists all set-up breaks.
- first argument sets up breakpoint at specific filename/function and line number.
- second argument gives option to break only on specific python condition
cl(ear) [filename:lineno | bpnumber [bpnumber ...]]
- without argument clears list of all set-up breaks.
- with first or second argument, gives option to distinct which breakpoints needs to be cleared.
s(tep) - executes current line
n(ext) - moves to next line of funtion or returns if not found.
r(eturn) - continue execution until current function returns.
q(uit) - quit from debugger.

The full documentation about commands can be found at the pdb documentation page on python docs

import pdb; pdb.set_trace()

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See you in the next episode! Cheers!