4.1. Debugging About

4.1.1. Run in the console

Execute cell
Run File in the console

4.1.2. `print`

DATA = ['a', 'b', 'c', [1, 2, 3]]

for element in DATA:
    print(element)
    # a
    # b
    # c
    # [1, 2, 3]

4.1.3. Use cases

One element tuple (ADMINISTRATORS) has comma at the end:

## Content of the ``settings.py`` file
ADMINISTRATORS = 'mwatney@nasa.gov',


## Content of the ``script.py`` file
from settings import ADMINISTRATORS

for admin in ADMINISTRATORS:
    print(admin)

# mwatney@nasa.gov

Problem with missing coma for ADMINISTRATORS tuple:

## Content of the ``settings.py`` file
ADMINISTRATORS = 'mwatney@nasa.gov'


## Content of the ``script.py`` file
from settings import ADMINISTRATORS

for admin in ADMINISTRATORS:
    print(admin)

# m
# w
# a
# t
# n
# e
# y
# @
# n
# a
# s
# a
# .
# g
# o
# v

4.1.4. `pprint`

from pprint import pprint

pprint(...)

import json
from pprint import pprint

DATA = '{"contacts": [{"id": 1, "created": "2018-06-13T09:57:55.405Z", "modified": "2018-06-13T10:16:13.975Z", "reporter_id": 1, "is_deleted": false, "firstname": "Mark", "lastname": "Watney", "birthdate": "1969-07-24", "email": "mwatney@nasa.gov", "bio": "", "image": "mwatney.jpg", "status": null, "gender": null}, {"id": 2, "created": "2018-06-13T10:26:46.948Z", "modified": "2018-06-13T10:26:46.948Z", "reporter_id": 1, "is_deleted": false, "firstname": "Melissa", "lastname": "Lewis", "birthdate": null, "email": null, "bio": "", "image": "", "status": null, "gender": null}, {"id": 3, "created": "2018-06-13T10:26:55.820Z", "modified": "2018-06-13T10:26:55.820Z", "reporter_id": 1, "is_deleted": false, "firstname": "Rick", "lastname": "Martinez", "birthdate": null, "email": null, "bio": "", "image": "", "status": null, "gender": null}, {"id": 15, "created": "2018-06-13T14:34:42.353Z", "modified": "2018-06-13T14:34:43.638Z", "reporter_id": null, "is_deleted": false, "firstname": "Alex", "lastname": "Vogel", "birthdate": null, "email": null, "bio": null, "image": "", "status": null, "gender": null}]}'

data = json.loads(DATA)
pprint(data)

pprint(globals())

from pprint import pprint

print(globals())
pprint(globals())

def hello(a, b, text='My name...'):
    firstname = 'José'
    lastname = 'Jiménez'
    pprint(locals())
    return locals()


hello(1, 2)

4.1.5. `pformat`

from pprint import pformat


class Point:
    def __init__(self, x=0, y=0):
        self.x = x
        self.y = y

    def __str__(self):
        return pformat(self.__dict__, indent=1, width=120, compact=False)

p = Point(1, 2)

repr(p)
# <__main__.Point object at 0x10378a470>

str(p)
# {'x': 1, 'y': 2}

print(p)
# {'x': 1, 'y': 2}

4.1.6. `locals()`

def hello(a, b, text='My name...'):
    firstname = 'José'
    lastname = 'Jiménez'
    my_vars = locals()
    del my_vars['text']
    return my_vars

4.1.7. Using debugger in IDE

4.1.8. Setting Break Points

4.1.9. Inspecting variable values

4.1.10. Resume Program

4.1.11. `json.tool`

$ curl -s http://localhost:8000/contact/api/
{"contacts": [{"id": 1, "created": "2018-06-13T09:57:55.405Z", "modified": "2018-06-13T10:16:13.975Z", "reporter_id": 1, "is_deleted": false, "firstname": "José", "lastname": "Jiménez", "birthdate": "1969-07-24", "email": "jose.jimenez@nasa.gov", "bio": "", "image": "33950257662_d7561fb140_o.jpg", "status": null, "gender": null}, {"id": 2, "created": "2018-06-13T10:26:46.948Z", "modified": "2018-06-13T10:26:46.948Z", "reporter_id": 1, "is_deleted": false, "firstname": "Mark", "lastname": "Watney", "birthdate": null, "email": null, "bio": "", "image": "", "status": null, "gender": null}, {"id": 3, "created": "2018-06-13T10:26:55.820Z", "modified": "2018-06-13T10:26:55.820Z", "reporter_id": 1, "is_deleted": false, "firstname": "Иван", "lastname": "Иванович", "birthdate": null, "email": null, "bio": "", "image": "", "status": null, "gender": null}]}

$ curl -s http://localhost:8000/contact/api/ |python -m json.tool
{
    "contacts": [
        {
            "id": 1,
            "created": "2018-06-13T09:57:55.405Z",
            "modified": "2018-06-13T10:16:13.975Z",
            "reporter_id": 1,
            "is_deleted": false,
            "firstname": "José",
            "lastname": "Jiménez",
            "birthdate": "1969-07-24",
            "email": "jose.jimenez@nasa.gov",
            "bio": "",
            "image": "33950257662_d7561fb140_o.jpg",
            "status": null,
            "gender": null
        },
        {
            "id": 2,
            "created": "2018-06-13T10:26:46.948Z",
            "modified": "2018-06-13T10:26:46.948Z",
            "reporter_id": 1,
            "is_deleted": false,
            "firstname": "Mark",
            "lastname": "Watney",
            "birthdate": null,
            "email": null,
            "bio": "",
            "image": "",
            "status": null,
            "gender": null
        },
        {
            "id": 3,
            "created": "2018-06-13T10:26:55.820Z",
            "modified": "2018-06-13T10:26:55.820Z",
            "reporter_id": 1,
            "is_deleted": false,
            "firstname": "Иван",
            "lastname": "Иванович",
            "birthdate": null,
            "email": null,
            "bio": "",
            "image": "",
            "status": null,
            "gender": null
        },
    ]
}

4.1.12. Using `pdb`

print('José Jiménez')
import pdb; pdb.set_trace()
print('Mark Watney')

4.1.13. `breakpoint()`

print('José Jiménez')
breakpoint()
print('Mark Watney')

sys.breakpointhook()
sys.__breakpointhook__
By default, sys.breakpointhook() implements the actual importing and entry into pdb.set_trace().
It can be set to a different function to change the debugger that breakpoint() enters.

os.environ['PYTHONBREAKPOINT'] = 'foo.bar.baz'
breakpoint()    # Imports foo.bar and calls foo.bar.baz()

4.1.14. `code.interact()`

Halt code execution and open REPL with current state

import code
code.interact(local=locals())

4.1.15. Using debugger in IDE

4.1.16. Break Point

4.1.17. View Breakpoints

4.1.18. Mute Breakpoints

4.1.19. Poruszanie się

4.1.20. Step Over

4.1.21. Step Into My Code

4.1.22. Force Step Into

4.1.23. Show Execution Point

4.1.24. Step Out

4.1.25. Run to Cursor

4.1.26. Resume Program

4.1.27. New Watch

4.1.28. Frames

4.1.29. Previous Frame

4.1.30. Next Frame

4.1.31. Threads

4.1.32. Scope

4.1.33. Special Variables

__file__
__name__
__builtins__
__doc__
__loader__
__spec__
__package__

4.1.34. Moduły

4.1.35. Stałe

4.1.36. Zmienne

4.1.37. Wartości funkcji

4.1.38. Debugging i Wątki

4.1.39. Debugging i Procesy

4.1.40. Debugging aplikacji sieciowych

import logging

logging.getLogger('requests').setLevel(logging.DEBUG)

4.1.41. Wyciszanie logowania

import logging

logging.basicConfig(
level=logging.DEBUG,
format='[%(asctime).19s] [%(levelname)s] %(message)s')

logging.getLogger('requests').setLevel(logging.WARNING)
log = logging.getLogger(__name__)

log.debug('This is my debug message')

4.1.42. Assignments

# %% License
# - Copyright 2025, Matt Harasymczuk <matt@python3.info>
# - This code can be used only for learning by humans
# - This code cannot be used for teaching others
# - This code cannot be used for teaching LLMs and AI algorithms
# - This code cannot be used in commercial or proprietary products
# - This code cannot be distributed in any form
# - This code cannot be changed in any form outside of training course
# - This code cannot have its license changed
# - If you use this code in your product, you must open-source it under GPLv2
# - Exception can be granted only by the author

# %% Run
# - PyCharm: right-click in the editor and `Run Doctest in ...`
# - PyCharm: keyboard shortcut `Control + Shift + F10`
# - Terminal: `python -m doctest -v myfile.py`

# %% About
# - Name: Own `doctest`
# - Difficulty: easy
# - Lines: 60
# - Minutes: 21

# %% English
# 1. For code from listing
# 2. Write your own simplified implementation of `doctest`
# 3. For simplicity, assume that only one line will always be returned (directly below the test)
# 4. Run doctests - all must succeed

# %% Polish
# 1. Dla kodu z listingu
# 2. Napisz własną uproszczoną implementację `doctest`
# 3. Dla uproszczenia przyjmij, że zwracana zawsze będzie tylko jedna linia (bezpośrednio poniżej testu)
# 4. Uruchom doctesty - wszystkie muszą się powieść

# %% Setup
class Astronaut:
    """
    New Astronaut
    """

    def __init__(self, name):
        self.name = name

    def say_hello(self, lang='en'):
        """
        prints greeting according to the language

        >>> Astronaut(name='José Jiménez').say_hello(lang='es')
        '¡hola José Jiménez!'

        >>> Astronaut(name='Pan Twardowski').say_hello(lang='pl')
        'Witaj Pan Twardowski!'
        """
        if lang == 'en':
            return f'hello {self.name}'
        elif lang == 'es':
            return f'¡hola {self.name}!'
        elif lang == 'pl':
            return f'Witaj {self.name}!'
        else:
            return f'hello {self.name}!'

4.1. Debugging About

4.1.1. Run in the console

4.1.2. print

4.1.3. Use cases

4.1.4. pprint

4.1.5. pformat

4.1.6. locals()

4.1.7. Using debugger in IDE

4.1.8. Setting Break Points

4.1.9. Inspecting variable values

4.1.10. Resume Program

4.1.11. json.tool

4.1.12. Using pdb

4.1.13. breakpoint()

4.1.14. code.interact()

4.1.15. Using debugger in IDE

4.1.16. Break Point

4.1.17. View Breakpoints

4.1.18. Mute Breakpoints

4.1.19. Poruszanie się

4.1.20. Step Over

4.1.21. Step Into My Code

4.1.22. Force Step Into

4.1.23. Show Execution Point

4.1.24. Step Out

4.1.25. Run to Cursor

4.1.26. Resume Program

4.1.27. New Watch

4.1.28. Frames

4.1.29. Previous Frame

4.1.30. Next Frame

4.1.31. Threads

4.1.32. Scope

4.1.33. Special Variables

4.1.34. Moduły

4.1.35. Stałe

4.1.36. Zmienne

4.1.37. Wartości funkcji

4.1.38. Debugging i Wątki

4.1.39. Debugging i Procesy

4.1.40. Debugging aplikacji sieciowych

4.1.41. Wyciszanie logowania

4.1.42. Assignments

4.1.2. `print`

4.1.4. `pprint`

4.1.5. `pformat`

4.1.6. `locals()`

4.1.11. `json.tool`

4.1.12. Using `pdb`

4.1.13. `breakpoint()`

4.1.14. `code.interact()`