Mar 12, 2013

Exceptions in Python

Today, we discuss about the following :
1) Try block in Python
2) finally block
3) Exceptions

-> In the following example, we can catch exceptions occurred in the code.

-> Keep the code in try block, when an exception is there, it is being caught by except

-> Finally block will be called at the last after the end of execution of the block.

-> In this example, there are few well know exceptions like FileNotFoundError, IOError, EOFError, ValueError


read.txt (Input File)

Abraham Lincoln
Mother Teresa
Paul Coelho

exceptions_test.py
  
import time
import sys

try:    
    f = open('read.txt', 'r') 
    while True: # our usual file-reading idiom
        line = f.readline()
        if len(line) == 0:
            break
        time.sleep(0.5)  #1/2 sec
        print(line)
except FileNotFoundError:
    print('\n File NOT Found Error')
    sys.exit
except IOError:
    print('\n IO Error')
    sys.exit
except EOFError:
    print('\nWhy did you do an EOF on me?')
    sys.exit
except ValueError:
    print("\nValue Error.")
    sys.exit
finally:
    f.close()
    print('Cleaning up...closed the file')
                                                    
                                           


You may also wish to read Object Oriented Concepts in Python as mentioned :
Python Class and Object Example
Inheritance in Python
Packages in Python



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