Comprensión de las excepciones

Introducción

¿Qué es una excepción?

# 1 / 0  # raises ZeroDivisionError
print('exceptions demo')

Jerarquía de excepciones

print(issubclass(ValueError, Exception))
print(issubclass(Exception, BaseException))

Excepciones integradas comunes

# Examples:
# int('abc')       -> ValueError
# d['missing']     -> KeyError
# [1,2][9]         -> IndexError
print('common exceptions')

El traceback

def f(): return 1/0
# f()  # shows traceback
print('traceback demo')

Objeto de excepción

try:
    int('abc')
except ValueError as e:
    print(type(e).__name__, e)

Capturar varios tipos

def parse(x):
    try:
        return int(x)
    except (TypeError, ValueError):
        return None
print(parse('abc'), parse(None))

El grupo de excepciones (3.11+)

# Python 3.11+:
# try: ...
# except* ValueError as eg:
#     print(eg.exceptions)
print('exception group demo')

Advertencias frente a excepciones

import warnings
warnings.warn('This is deprecated', DeprecationWarning)
print('warning issued')

sys.exc_info()

import sys
try:
    1/0
except:
    exc_type, exc_val, _ = sys.exc_info()
    print(exc_type, exc_val)

Encadenamiento de excepciones

try:
    int('abc')
except ValueError as e:
    raise RuntimeError('parse failed') from e

Comprobación rápida

Resumen

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