Exceptional Handling-

  • – Exception is a class.
  • – If we will not handle the exceptions in our code then PVM will call its default exceptional handler to handle the exception.
  • – One try block can have multiple except to handle the different-2 exceptions.

Format Of Using Exception Handling

  • – try-except
  • – try-finally
  • – try-except-except
  • – try-except-finally
  • – try-except-except-finally

Note-

Only try without except and finally is not possible.

Ex-
class Test:
    def main():
        a = int(input("Please enter the 1st no.-"))
        b = int(input("Please enter the 2nd no.-"))
        try:
            c = a/b
            print("Result-", c)
        except ZeroDivisionError:
            print("ZeroDivisionError found")
        except Exception as e:
            print("Other error", e)
        finally:
            print("Finally called")
Test.main()

Output-
	Please enter the 1st no.-4
	Please enter the 2nd no.-2
	Result- 2.0
	Finally called

Raise-

  • – If user defined exception is there then we need to extend the behavior of parent class means Exception class.
  • – At the time of object creation of user defined exception class, raise keyword is used to raise the object.

Ex-

class MyError(Exception):
    def __init__(self, name):
        self.name = name

class RaiseExc:
    def main():
        obj = MyError('User defined exception')
        raise obj

RaiseExc.main()

  • Qsn-

    How can we handle the exception in Python?

  • Ans-

    We can handle the exception by two ways.

  • 1) At The Time Of Definition Of Function

  • 2) At the time of calling the function(Recommended to use)

1) At The Time Of Definition Of Function

Ex-

class MyError(Exception):
    def __init__(self, name):
        self.name = name

class Test:
    def fun():
        obj = MyError("Exception string")
        try:
            raise obj
        except MyError as ex:
            print("Exception found-", ex)

class RaiseExc:
    def main():
        Test.fun()

RaiseExc.main()
Output-
	Exception found- Error string

2) At The Time Of Calling The Function-

Ex-

class MyError(Exception):
    def __init__(self, name):
        self.name = name

class Test:
    def m_test():
        obj = MyError("Error string")
        raise obj

class RaiseExc:
    def main():
        try:
            Test.m_test()
        except Exception as ex:
            print("Exception found-", ex)

RaiseExc.main()
Output-
	Exception found- Error string
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