So cute are you python 7

#!/usr/bin/evn python
#coding:utf-8
#FileName:using_file.py
#function:Show how to use python to operation a file simply.
#History:12-10-2013
poem ='''\
Programing is fun
When the work is done
if you wanna make your work also fun:
Using python!
'''
f = file('poem.txt','w')#open a file for writing.
f.write(poem)#Write text to file
f.close()#close the file.

f =file('poem.txt')
#if no mode os specified,'r'ead mode is assumed by default.
while True:
line=f.readline()
if len(line)== 0:
#print 'No contents on poem.txt'
break
print line,
# Notice comma to avoid automatic newline aded by python
f.close()#close the file.

#!/usr/bin/evn python
#coding:utf-8
#FileName:pickling.py
#function:Show how to use python to pickling things with cPickle module
#then read back from the storage
#History:12-10-2013
import cPickle as p
#import pickle module
shoplistfile ='shoplist.data'
#the name of the file where we will store the object

shoplist = ['apple','mange','carrat']

#write to the file
f =file(shoplistfile,'w')
p.dump(shoplist,f)#dump the object to a file
f.close()

del shoplist #remove the sjoplist

#read back from the storage
f=file(shoplistfile)
storedlist=p.load(f)
print storedlist

#!/usr/bin/evn python
#coding:utf-8
#FileName:try_except.py
#function:Show how to use python to catch exceptios and deal with it.
#History:12-10-2013

import sys

try:
s=raw_input('Enter something-->')
except EOFError:
print '\nWhy did you do an EOF on me?'
sys.exit()#Exit the program.
except:
print '\nSome error/exception occurred.'
#here,we are not exiting the program

print 'Works Done!\r\n'

#!/usr/bin/evn python
#coding:utf-8
#FileName:raising.py
#function:Show how to use python to catch exceptions by using raising

class ShortInputException(Exception):
'''A user-defined exception class.'''
def __init__(self,length,atleast):
Exception.__init__(self)
self.length=length
self.atleast=atleast

try:
s=raw_input('Enter something-->')
if len(s)< 3:
raise ShortInputException(len(s), 3)
#other work can continue as usual here
except EOFError:
print '\nWhy did you do an EOF on me ?'
except ShortInputException,x:
print 'ShortInputException:The input was of length %d,\
was excepting at least %d'%(x.length,x.atleast)
else:
print 'No exception was raised.'

#!/usr/bin/evn python
#coding:utf-8
#FileName:finally.py
#function:Show how to use python to Using try finally
#history:12-10-2013
import time

try:
f=file('poem.txt')
while True:
line =f.readline()
if len(line)== 0:
break
time.sleep( 2)
print line,
finally:
f.close()
print 'Cleaning up...closed the file.'