Revisions to Handling exceptions in Python 3

Typo fix

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edited Jan 8, 2021 at 7:41

88.4k
14
104
327

Rather than using as e then raise e you can just omit e.

except KeyboardInterrupt as e:
    raise e

except KeyboardInterrupt:
    raise

Rather than specifying an except block for KeyboardInterrupt and SystemExit you can just specify them in the same except by passing a tuple.
```
except KeyboardInterrupt:
    raise
except SystemExit:
    raise
```
```
except (KeyboardInterrupt, SystemExit):
    raise
```
Both KeyboardInterrupt and SystemExit are not subclasses of Exception so you do not need to handle them. The exceptions will propagate like normal.

You may want to familiarize yourself with the exception hirarchyhierarchy.

You can get all the information that sys.exc_info() gives from e.

exc_type, exc_obj, exc_tb = sys.exc_info()

exc_type, exc_obj, exc_tb = type(e), e, e.__traceback__

You can get the current frame from exc_tb rather than inspect.currentframe(). This makes the code more portable if you ever decide to move the code into a function to format tracebacks.
```
frame = inspect.currentframe()
```
```
frame = exc_tb.tb_frame
```
Please follow PEP 8 and name variables with snake_case. It is very easy to see the code you've taken from the Python docs and the code you've written yourself / taken from somewhere else.

If you're going to hard code the == at least use * to build it the size you want.

print('=======================================================================================================')

print('=' * 103)

Better yet just print to the size of the terminal.
```
print('=' * os.get_terminal_size().columns)
```

I would prefer to use f-strings if available.

print('Unhandled exception: ', exc_type, script_name, 'at line', exc_tb.tb_lineno)

print(f'Unhandled exception:  {exc_type} {script_name} at line {exc_tb.tb_lineno}')

Rather than using as e then raise e you can just omit e.

except KeyboardInterrupt as e:
    raise e

except KeyboardInterrupt:
    raise

Rather than specifying an except block for KeyboardInterrupt and SystemExit you can just specify them in the same except by passing a tuple.
```
except KeyboardInterrupt:
    raise
except SystemExit:
    raise
```
```
except (KeyboardInterrupt, SystemExit):
    raise
```
Both KeyboardInterrupt and SystemExit are not subclasses of Exception so you do not need to handle them. The exceptions will propagate like normal.

You may want to familiarize yourself with the exception hirarchy.

You can get all the information that sys.exc_info() gives from e.

exc_type, exc_obj, exc_tb = sys.exc_info()

exc_type, exc_obj, exc_tb = type(e), e, e.__traceback__

You can get the current frame from exc_tb rather than inspect.currentframe(). This makes the code more portable if you ever decide to move the code into a function to format tracebacks.
```
frame = inspect.currentframe()
```
```
frame = exc_tb.tb_frame
```
Please follow PEP 8 and name variables with snake_case. It is very easy to see the code you've taken from the Python docs and the code you've written yourself / taken from somewhere else.

If you're going to hard code the == at least use * to build it the size you want.

print('=======================================================================================================')

print('=' * 103)

Better yet just print to the size of the terminal.
```
print('=' * os.get_terminal_size().columns)
```

I would prefer to use f-strings if available.

print('Unhandled exception: ', exc_type, script_name, 'at line', exc_tb.tb_lineno)

print(f'Unhandled exception:  {exc_type} {script_name} at line {exc_tb.tb_lineno}')

Rather than using as e then raise e you can just omit e.

except KeyboardInterrupt as e:
    raise e

except KeyboardInterrupt:
    raise

Rather than specifying an except block for KeyboardInterrupt and SystemExit you can just specify them in the same except by passing a tuple.
```
except KeyboardInterrupt:
    raise
except SystemExit:
    raise
```
```
except (KeyboardInterrupt, SystemExit):
    raise
```
Both KeyboardInterrupt and SystemExit are not subclasses of Exception so you do not need to handle them. The exceptions will propagate like normal.

You may want to familiarize yourself with the exception hierarchy.

You can get all the information that sys.exc_info() gives from e.

exc_type, exc_obj, exc_tb = sys.exc_info()

exc_type, exc_obj, exc_tb = type(e), e, e.__traceback__

You can get the current frame from exc_tb rather than inspect.currentframe(). This makes the code more portable if you ever decide to move the code into a function to format tracebacks.
```
frame = inspect.currentframe()
```
```
frame = exc_tb.tb_frame
```
Please follow PEP 8 and name variables with snake_case. It is very easy to see the code you've taken from the Python docs and the code you've written yourself / taken from somewhere else.

If you're going to hard code the == at least use * to build it the size you want.

print('=======================================================================================================')

print('=' * 103)

Better yet just print to the size of the terminal.
```
print('=' * os.get_terminal_size().columns)
```

I would prefer to use f-strings if available.

print('Unhandled exception: ', exc_type, script_name, 'at line', exc_tb.tb_lineno)

print(f'Unhandled exception:  {exc_type} {script_name} at line {exc_tb.tb_lineno}')

Show which code is quoted from question as a quote

Source Link

edited Jan 7, 2021 at 15:55

Toby Speight

88.4k
14
104
327

Rather than using as e then raise e you can just omit e.

except KeyboardInterrupt as e:
    raise e

except KeyboardInterrupt as e:
    raise e

except KeyboardInterrupt:
    raise

Rather than specifying an except block for KeyboardInterrupt and SystemExit you can just specify them in the same except by passing a tuple.

except KeyboardInterrupt:
    raise
except SystemExit:
    raise

except KeyboardInterrupt:
    raise
except SystemExit:
    raise

except (KeyboardInterrupt, SystemExit):
    raise

Both KeyboardInterrupt and SystemExit are not subclasses of Exception so you do not need to handle them. The exceptions will propagate like normal.

You may want to familiarize yourself with the exception hirarchy.

You can get all the information that sys.exc_info() gives from e.

exc_type, exc_obj, exc_tb = sys.exc_info()

exc_type, exc_obj, exc_tb = sys.exc_info()

exc_type, exc_obj, exc_tb = type(e), e, e.__traceback__

You can get the current frame from exc_tb rather than inspect.currentframe(). This makes the code more portable if you ever decide to move the code into a function to format tracebacks.
```
frame = inspect.currentframe()
```
```
frame = inspect.currentframe()
```
```
frame = exc_tb.tb_frame
```
Please follow PEP 8 and name variables with snake_case. It is very easy to see the code you've taken from the Python docs and the code you've written yourself / taken from somewhere else.

If you're going to hard code the == at least use * to build it the size you want.

print('=======================================================================================================')

print('=======================================================================================================')

print('=' * 103)

Better yet just print to the size of the terminal.
```
print('=' * os.get_terminal_size().columns)
```

I would prefer to use f-strings if available.

print('Unhandled exception: ', exc_type, script_name, 'at line', exc_tb.tb_lineno)

print('Unhandled exception: ', exc_type, script_name, 'at line', exc_tb.tb_lineno)

print(f'Unhandled exception:  {exc_type} {script_name} at line {exc_tb.tb_lineno}')

Rather than using as e then raise e you can just omit e.

except KeyboardInterrupt as e:
    raise e

except KeyboardInterrupt:
    raise

Rather than specifying an except block for KeyboardInterrupt and SystemExit you can just specify them in the same except by passing a tuple.
```
except KeyboardInterrupt:
    raise
except SystemExit:
    raise
```
```
except (KeyboardInterrupt, SystemExit):
    raise
```
Both KeyboardInterrupt and SystemExit are not subclasses of Exception so you do not need to handle them. The exceptions will propagate like normal.

You may want to familiarize yourself with the exception hirarchy.

You can get all the information that sys.exc_info() gives from e.

exc_type, exc_obj, exc_tb = sys.exc_info()

exc_type, exc_obj, exc_tb = type(e), e, e.__traceback__

You can get the current frame from exc_tb rather than inspect.currentframe(). This makes the code more portable if you ever decide to move the code into a function to format tracebacks.
```
frame = inspect.currentframe()
```
```
frame = exc_tb.tb_frame
```
Please follow PEP 8 and name variables with snake_case. It is very easy to see the code you've taken from the Python docs and the code you've written yourself / taken from somewhere else.

If you're going to hard code the == at least use * to build it the size you want.

print('=======================================================================================================')

print('=' * 103)

Better yet just print to the size of the terminal.
```
print('=' * os.get_terminal_size().columns)
```

I would prefer to use f-strings if available.

print('Unhandled exception: ', exc_type, script_name, 'at line', exc_tb.tb_lineno)

print(f'Unhandled exception:  {exc_type} {script_name} at line {exc_tb.tb_lineno}')

Rather than using as e then raise e you can just omit e.

except KeyboardInterrupt as e:
    raise e

except KeyboardInterrupt:
    raise

Rather than specifying an except block for KeyboardInterrupt and SystemExit you can just specify them in the same except by passing a tuple.
```
except KeyboardInterrupt:
    raise
except SystemExit:
    raise
```
```
except (KeyboardInterrupt, SystemExit):
    raise
```
Both KeyboardInterrupt and SystemExit are not subclasses of Exception so you do not need to handle them. The exceptions will propagate like normal.

You may want to familiarize yourself with the exception hirarchy.

You can get all the information that sys.exc_info() gives from e.

exc_type, exc_obj, exc_tb = sys.exc_info()

exc_type, exc_obj, exc_tb = type(e), e, e.__traceback__

You can get the current frame from exc_tb rather than inspect.currentframe(). This makes the code more portable if you ever decide to move the code into a function to format tracebacks.
```
frame = inspect.currentframe()
```
```
frame = exc_tb.tb_frame
```
Please follow PEP 8 and name variables with snake_case. It is very easy to see the code you've taken from the Python docs and the code you've written yourself / taken from somewhere else.

If you're going to hard code the == at least use * to build it the size you want.

print('=======================================================================================================')

print('=' * 103)

Better yet just print to the size of the terminal.
```
print('=' * os.get_terminal_size().columns)
```

I would prefer to use f-strings if available.

print('Unhandled exception: ', exc_type, script_name, 'at line', exc_tb.tb_lineno)

print(f'Unhandled exception:  {exc_type} {script_name} at line {exc_tb.tb_lineno}')

Source Link

answered Jan 7, 2021 at 15:20

Peilonrayz ♦

44.6k
7
80
158

Rather than using as e then raise e you can just omit e.

except KeyboardInterrupt as e:
    raise e

except KeyboardInterrupt:
    raise

Rather than specifying an except block for KeyboardInterrupt and SystemExit you can just specify them in the same except by passing a tuple.
```
except KeyboardInterrupt:
    raise
except SystemExit:
    raise
```
```
except (KeyboardInterrupt, SystemExit):
    raise
```
Both KeyboardInterrupt and SystemExit are not subclasses of Exception so you do not need to handle them. The exceptions will propagate like normal.

You may want to familiarize yourself with the exception hirarchy.

You can get all the information that sys.exc_info() gives from e.

exc_type, exc_obj, exc_tb = sys.exc_info()

exc_type, exc_obj, exc_tb = type(e), e, e.__traceback__

You can get the current frame from exc_tb rather than inspect.currentframe(). This makes the code more portable if you ever decide to move the code into a function to format tracebacks.
```
frame = inspect.currentframe()
```
```
frame = exc_tb.tb_frame
```
Please follow PEP 8 and name variables with snake_case. It is very easy to see the code you've taken from the Python docs and the code you've written yourself / taken from somewhere else.

If you're going to hard code the == at least use * to build it the size you want.

print('=======================================================================================================')

print('=' * 103)

Better yet just print to the size of the terminal.
```
print('=' * os.get_terminal_size().columns)
```

I would prefer to use f-strings if available.

print('Unhandled exception: ', exc_type, script_name, 'at line', exc_tb.tb_lineno)

print(f'Unhandled exception:  {exc_type} {script_name} at line {exc_tb.tb_lineno}')

if __name__ == '__main__':
    try:
        x = 42/0
    except Exception as e:
        exc_tb = e.__traceback__
        script_name = os.path.split(exc_tb.tb_frame.f_code.co_filename)[1]
        function_name = exc_tb.tb_frame.f_code.co_name
        print('=' * os.get_terminal_size().columns)
        print(f'Unhandled exception:  {type(e)} {script_name} at line {exc_tb.tb_lineno}')
        print(f'                      in function {function_name}')
        print(f'                      {e}')

        traceback.print_exc()
        raise SystemExit(1)

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