python_general

Python General

Using the Pdb debugger

Run the Pdb debugger

python -m pdb main.py

Halt at beginning of execution

export PYTHONBREAKPOINT=pdb.set_trace
python main.py

Break at exception

import sys, pdb; sys.excepthook = lambda exctype, value, tb: (print("Unhandled exception detected. Entering debugger..."), pdb.post_mortem(tb))

Set breakpoint

breakpoint()

Useful commands

To be used within a debug prompt.

Breakpoint navigation

# Continue exec until next breakpoint
continue
# Step over (exec line but don't step into func)
next

# Step into (enter func & stop at 1st line inside it)
step
# Return from current func
return

Break at file::line

break relative/path/to/script.py:10

Note that you cannot break at comments / empty lines / ...

Break at function name

break my_func

Conditional breakpoints

break relative/path/to/script.py:10, x > 5

Disable n breakpoints

disable
# same as:
disable 1
# disable all
disable all

You need to continue if you don't want to stay in the current break.

Inspect objects

Print the structure of a whole object via pprint.pprint(vars(...)):

import pprint

# Object to inspect
class PhysicalFunction:
    def __init__(self):
        self.name = "ExampleFunction"
        self.parameters = {
            "param1": 10,
            "param2": 20,
            "param3": [1, 2, 3, 4, 5],
            "param4": {"subparam1": "value1", "subparam2": "value2"}
        }
        self.description = ("This is a detailed description of the ExampleFunction. "
                            "It includes multiple parameters and nested structures.")

attributes = pprint.pprint(vars(PhysicalFunction()))

Output:

{'description': 'This is a detailed description of the ExampleFunction. It '
                'includes multiple parameters and nested structures.',
 'name': 'ExampleFunction',
 'parameters': {'param1': 10,
                'param2': 20,
                'param3': [1, 2, 3, 4, 5],
                'param4': {'subparam1': 'value1', 'subparam2': 'value2'}}}