[PYTHON] Catch multiple types of exceptions

1

import sys, traceback

number1 = 100
number2 = 'a'

print('strat')

try:
    answer = number1 / number2
    print(answer)
except ZeroDivisionError as e:
    print('It does not break at 0.')
    sys.stderr.write(traceback.format_exc())
except NameError as e:
    print('Calling an undefined variable')
    sys.stderr.write(traceback.format_exc())
except Exception as e:
    print('An unexpected error has occurred.')
    sys.stderr.write(traceback.format_exc())
finally:
    print('end')

Execution result of 1

strat
An unexpected error has occurred.
end

1 run-time error

Traceback (most recent call last):
  File "Main.py", line 9, in <module>
    answer = number1 / number2
TypeError: unsupported operand type(s) for /: 'int' and 'str'

Since number2 ='a', TypeError has occurred.

TypeError is except ZeroDivisionError、 It cannot be captured by except NameError, Can be caught with except Exception.

Exception is a superclass of ZeroDivisionError and NameError. To put it the other way around It is a subclass of ZeroDivisionError and NameError.

Exception can catch all exceptions, Subclasses are a more specific exception.

When catching multiple exceptions It is checked whether there is a corresponding except block in order from the top. For that reason, You need to start with a more specific subclass.

Otherwise, The except Exception block, which catches all exceptions, Before the subclasses that can catch exceptions more specifically move It catches an exception.

2

import sys,traceback

number1 = 100
number2 = 0

print('start')

try:
    answer = number1 / number2
    print(answer)
except Exception as e:
    print('An unexpected exception has occurred.')
    sys.stderr.write(traceback.format_exc())
except ZeroDivisionError as e:
    print('It does not break at 0.')
    sys.stderr.write(traceback.format_exc())
except NameError as e:
    print('You called an undefined variable.')
    sys.stderr.write(traceback.format_exc())
finally:
    print('end')

Execution result of 2

strat
An unexpected error has occurred.
end

2 run-time error

Traceback (most recent call last):
  File "Main.py", line 9, in <module>
    answer = number1 / number2
ZeroDivisionError: division by zero

I wanted to output "0 does not break", but Because the superclass Exception catches any exception The except Exception block has caught an exception.