Exception Handling

In this article you will learn how you will handle the exception to prevent your program getting crash by using try, except and finally statement. This will help to enhance the readability and clarity.

During writing the program we always think about their program logic and syntax but in spite of there being some program occurring due the exception and program will crash automatically and stop the program for further proceedings.

In this case we will use Python Built-in Exception to escape the program from crashing.

Here are some common built in Function in Python Programming along with errors, that cause them are listed below.

Keywords are used in exception handling ?

Try :

Suspecial code comes under this block.

Except:

This block has handle form the error

Finally :

The finally block lets you execute code, regardless of the result of the try- and except blocks.

Lets understand by the program

Program:

a=int(input("Enter Number"))
b=int(input("Second Number"))
print("Division",a/b)
print("Addition",a+b)

In this program you will see that there is no logical and syntax mistakes

Output:

Enter Number56
Second Number55
Division 1.018181818181818
Addition 111

But you are put zero value in ”B”

Enter Number12
Second Number0
Traceback (most recent call last):
  File "C:/Users/laptop/AppData/Local/Programs/Python/Python38-32/cal.py", line 3, in 
	print("Division",a/b)
ZeroDivisionError: division by zero

Error – ZeroDivisionError(this is called exception) ,addition syntax was correct but output wasl not display due to program crash .

lets understand another example

If assign string value in both variable:-

Enter Number"INDIA"
Traceback (most recent call last):
  File "C:/Users/laptop/AppData/Local/Programs/Python/Python38-32/cal.py", line 1, in 
	a=int(input("Enter Number"))
ValueError: invalid literal for int() with base 10: '"INDIA"'

ValueError(this is exception)

Let’s use the same program using exception handling

a=int(input("Enter Number"))
b=int(input("Second Number"))
try:
       	print("Division",a/b)

except ValueError:
       	print("Value error")
except ZeroDivisionError:
       	print("Putting Value Zero")
print("Addition",a+b)

Output:

Enter Number44
Second Number0
Putting Value Zero
Addition 44

Program 2:

try:
    f=open("abc.txt","r")
except FileNotFoundError:
    print("Not Found")
else:
    print(f.read())
    f.close()
finally:
   print(“Hi am finally block Run all time”)   

When the file ‘abc.txt’ does not exist.

Output:

Not Found
Hi am finally block Run all time

When the file ‘abc.txt’ exists.

Output:

India Is a great Country
Hi am finally block Run all time