Mine is the python debugger. I was a long holdout thinking that print statements were sufficient. That was untill I started having errors crop up in functions that took minutes to run. The thing that I most notably wish I would have known about is post_mortem.
Example
[ins] In [4]: def repeater(msg, repeats=1):
...: "repeats messages {repeats} number of times"
...: print(f'{msg}\n' * repeats)
[ins] In [5]: repeater('hi', 3)
hi
hi
hi
[ins] In [6]: repeater('hi', 'a')
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-6-0ec595774c81> in <module>
----> 1 repeater('hi', 'a')
<ipython-input-4-530890de75cd> in repeater(msg, repeats)
1 def repeater(msg, repeats=1):
2 "repeats messages {repeats} number of times"
----> 3 print(f'{msg}\n' * repeats)
4
Debug with iPython/Jupyter
%debug
Vanilla Debug
import pdb
import sys
pdb.post_mortem(sys.last_traceback)
More
For more information about the debugger checkout the real python article. https://realpython.com/python-debugging-pdb/
Also keep a bookmark of the table of pdb commands from the article https://realpython.com/python-debugging-pdb/#essential-pdb-commands
Debug Session
