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Defining Clean Up Actions in Python

Think of a task you will always want your program to do, whether it runs perfectly or raise any kind of error. For example, We use of try statement which has an optional clause – “finally” to perform clean up actions, that must be executed under all conditions.
Cleanup actions: Before leaving the try statement, “finally” clause is always executed, whether any exception is raised or not. These are clauses which are intended to define clean-up actions that must be executed under all circumstances.
Whenever an exception occurs and is not being handled by the except clause, first finally will occur and then the error is raised as default [Code 3].

Python Programs illustrating “Defining Clean Up Actions”

Code 1 : Code works normally and clean-up action is taken at the end

# Python code to illustrate
# clean up actions
def divide(x, y):
    try:
        # Floor Division : Gives only Fractional Part as Answer
        result = x // y
    except ZeroDivisionError:
        print("Sorry ! You are dividing by zero ")
    else:
        print("Yeah ! Your answer is :", result)
    finally:
        print("I'm finally clause, always raised !! ")
  
# Look at parameters and note the working of Program
divide(3, 2)

Output :

Yeah ! Your answer is : 1
I'm finally clause, always raised !! 

 
Code 2 : Code raise error and is carefully handled in the except clause. Note that Clean-up action is taken at the end.



# Python code to illustrate
# clean up actions
def divide(x, y):
    try:
        # Floor Division : Gives only Fractional Part as Answer
        result = x // y
    except ZeroDivisionError:
        print("Sorry ! You are dividing by zero ")
    else:
        print("Yeah ! Your answer is :", result)
    finally:
        print("I'm finally clause, always raised !! ")
  
# Look at parameters and note the working of Program
divide(3, 0)

/div>

Output :

Sorry ! You are dividing by zero 
I'm finally clause, always raised !!

 

Code 3 : Code, raise error but we don’t have any except clause to handle it. So, clean-up action is taken first and then the error(by default) is raised by the compiler.

# Python code to illustrate
# clean up actions
def divide(x, y):
    try:
        # Floor Division : Gives only Fractional Part as Answer
        result = x // y
    except ZeroDivisionError:
        print("Sorry ! You are dividing by zero ")
    else:
        print("Yeah ! Your answer is :", result)
    finally:
        print("I'm finally clause, always raised !! ")
  
# Look at parameters and note the working of Program
divide(3, "3")

Output :

I'm finally clause, always raised !! 

Error:

Traceback (most recent call last):
  File "C:/Users/DELL/Desktop/Code.py", line 15, in 
    divide(3, "3")
  File "C:/Users/DELL/Desktop/Code.py", line 7, in divide
    result = x // y
TypeError: unsupported operand type(s) for //: 'int' and 'str'

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.



This article is attributed to GeeksforGeeks.org

tags:

Python

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