Question

(Python)

Exercise-1: Raising Exceptions

Try the following code one by one:

raise NameError(‘Name not Found’)

raise IndexError("Sorry, index not found!")

raise KeyError("Sorry, my fault!")

What it does?

Exercise-2: Raising Exceptions

Try the following code:

try

:

raise

NameError(

'Name not found'

)

except

NameError:

print

(

'caught it'

)

What it does?

Exercise-3: Raising Exceptions using class

Here is an example related to RuntimeError. Here, a class is created that is a sub-class

from RuntimeError. This is useful when you need to display more specific information when an

exception is caught. In the try block, the user-defined exception is raised and caught in the except

block.

Try the following code:

class MyException(Exception):

pass

# MyException classinherits from the Exception class

raise MyException("Caught MyException")

What it does?

Now, add the try/finally block as shown below:

class MyException(Exception):

pass

# MyException classinherits from the Exception class

try:

raise MyException("Caught MyException")

finally:

print ("Done")

What it does?

Answer 1

Exercise 1

File Edit View Insert Cell Kernel Widgets Help Trusted Python 3 O a + D + Run C Code Download GitHub Binder In [1]: raise NameError('Name not Found') #we are explictly throwing a built-in exception called NameError, #as well as the message to be displayed in the exception Name Error Traceback (most recent call last) <ipython-input-1-66864151dcef> in <module> ----> 1 raise NameError('Name not Found') NameError: Name not Found In [2]: raise IndexError("Sorry, index not found!")#we are explictly throwing a built-in exception called IndexError, #as well as the message to be displayed in the exception IndexError Traceback (most recent call last) <ipython-input-2-5bc5606a1f9e> in <module> ----> 1 raise IndexError("Sorry, index not found!") #we are explictly throwing a built-in exception called IndexError, 2 #as well as the message to be displayed in the exception IndexError: Sorry, index not found! In [3]: raise KeyError("Sorry, my fault!") #we are explictly throwing a built-in exception called KeyError, #as well as the message to be displayed in the exception KeyError Traceback (most recent call last) <ipython-input-3-ab9c35378c28> in <module> ----> 1 raise KeyError("Sorry, my fault!")#we are explictly throwing a built-in exception called KeyError, 2 #as well as the message to be displayed in the exception KeyError: 'Sorry, my fault!' In [ ]:

2 and 3

File Edit View Insert Cell Kernel Widgets Help Trusted Python 3 O In [4]: try:#creating a try catch block. In a try except block, if we come across an exception in try, we can handle it inside except raise NameError('Name not found') #explictly throw an exceptiom except NameError:#this Lines mean if in the above try block, a NameError exception is thrown, then the execution will #move inside this except block print('caught it')#we are printing this line to show that we have caught the exception caught it In [5]: class MyException(Exception): #this is a custom class which is a sub class of Exception class, so we can throw it as an exception pass # MyException classinherits from the Exception class raise MyException("Caught My Exception")#throwing the above created exception class My Exception Traceback (most recent call last) <ipython-input-5-92ce2e39dd5a> in <module> 2 pass 3 # My Exception classinherits from the Exception class ----> 4 raise My Exception("Caught My Exception") #throwing the above created exception class MyException: Caught MyException In [6]: class MyException (Exception): pass# MyException classinherits from the Exception class try: raise My Exception("Caught MyException") finally:#a finally blockis guranteed to run, aftr a try except or try block. #The finally block will run even if no exception is caught print ("Done") #above code will throw exception as well as print Done. Done My Exception Traceback (most recent call last) <ipython-input-6-8ddef6dce345> in <module> 2 pass# MyException classinherits from the Exception class 3 try: ----> 4 raise My Exception("Caught My Exception") 5 finally:#a finally blockis guranteed to run, aftr a try except or try block. #The finally block will run even if no exception is caught MyException: Caught MyException