python class exception code example

Example 1: throwing an exception python

raise Exception("message")

Example 2: python exception

try:
   # Code to test / execute
   print('Test')
except (SyntaxError, IndexError) as E:  # specific exceptions
   # Code in case of SyntaxError for example
   print('Synthax or index error !')
except :
   # Code for any other exception
   print('Other error !')
else:
   # Code if no exception caught
   print('No error')
finally:
   # Code executed after try block (success) or any exception (ie everytime)
   print('Done')

# This code is out of try / catch bloc
print('Anything else')

Example 3: exception types python

BaseException
   ] SystemExit
   ] KeyboardInterrupt
   ] GeneratorExit
   ] Exception
        ] StopIteration
        ] StopAsyncIteration
        ] ArithmeticError
        |    ] FloatingPointError
        |    ] OverflowError
        |    ] ZeroDivisionError
        ] AssertionError
        ] AttributeError
        ] BufferError
        ] EOFError
        ] ImportError
        |    ] ModuleNotFoundError
        ] LookupError
        |    ] IndexError
        |    ] KeyError
        ] MemoryError
        ] NameError
        |    ] UnboundLocalError
        ] OSError
        |    ] BlockingIOError
        |    ] ChildProcessError
        |    ] ConnectionError
        |    |    ] BrokenPipeError
        |    |    ] ConnectionAbortedError
        |    |    ] ConnectionRefusedError
        |    |    ] ConnectionResetError
        |    ] FileExistsError
        |    ] FileNotFoundError
        |    ] InterruptedError
        |    ] IsADirectoryError
        |    ] NotADirectoryError
        |    ] PermissionError
        |    ] ProcessLookupError
        |    ] TimeoutError
        ] ReferenceError
        ] RuntimeError
        |    ] NotImplementedError
        |    ] RecursionError
        ] SyntaxError
        |    ] IndentationError
        |         ] TabError
        ] SystemError
        ] TypeError
        ] ValueError
        |    ] UnicodeError
        |         ] UnicodeDecodeError
        |         ] UnicodeEncodeError
        |         ] UnicodeTranslateError
        ] Warning
             ] DeprecationWarning
             ] PendingDeprecationWarning
             ] RuntimeWarning
             ] SyntaxWarning
             ] UserWarning
             ] FutureWarning
             ] ImportWarning
             ] UnicodeWarning
             ] BytesWarning
             ] ResourceWarning

Example 4: python exception

try:
  # code block
except ValueError as ve:
  print(ve)

Example 5: index error in python

# main.py
import datetime

from gw_utility.book import Book
from gw_utility.logging import Logging


def main():
    try:
        # Create list and populate with Books.
        books = list()
        books.append(Book("Shadow of a Dark Queen", "Raymond E. Feist", 497, datetime.date(1994, 1, 1)))
        books.append(Book("Rise of a Merchant Prince", "Raymond E. Feist", 479, datetime.date(1995, 5, 1)))
        books.append(Book("Rage of a Demon King", "Raymond E. Feist", 436, datetime.date(1997, 4, 1)))

        # Output Books in list, with and without index.
        Logging.line_separator('Books')
        log_list(books)
        Logging.line_separator('Books w/ index')
        log_list(books, True)
        # Output list element outside bounds.
        Logging.line_separator('books[len(books)]')
        Logging.log(f'books[{len(books)}]: {books[len(books)]}')
    except IndexError as error:
        # Output expected IndexErrors.
        Logging.log_exception(error)
    except Exception as exception:
        # Output unexpected Exceptions.
        Logging.log_exception(exception, False)


def log_list(collection, include_index=False):
    """Logs the each element in collection to the console.

    :param collection: Collection to be iterated and output.
    :param include_index: Determines if index is also output.
    :return: None
    """
    try:
        # Iterate by converting to enumeration.
        for index, item in enumerate(collection):
            if include_index:
                Logging.log(f'collection[{index}]: {item}')
            else:
                Logging.log(item)
    except IndexError as error:
        # Output expected IndexErrors.
        Logging.log_exception(error)
    except Exception as exception:
        # Output unexpected Exceptions.
        Logging.log_exception(exception, False)


if __name__ == "__main__":
    main()