Factorial of a Number

# Python program to find the factorial of a number provided by the user.


num = int(input("Enter a number: "))

factorial = 1

# check if the number is negative, positive or zero
if num < 0:
   print("Sorry, factorial does not exist for negative numbers")
elif num == 0:
   print("The factorial of 0 is 1")
else:
   for i in range(1,num + 1):
       factorial = factorial*i
   print("The factorial of",num,"is",factorial)

Lisiting particular type of files in a directory

import os
Path = os.getcwd()
Names= os.listdir(Path)
h=raw_input('Enter the file type extension: ')
for n in Names:
      if h in n:
            print n

Enter the sum of n numbers using file

n=int(raw_input('Enter the n for sum of n numbers: '))
f=open('integers.txt','w')
for count in range(n+1):
      f.write(str(count)+"\n")
f.close()

f=open('integers.txt','r')
sum=0
for l in f:
      l=l.strip()
      number=int(l)
      sum+=number
print 'The sum is',sum

Writing and reading integers from a file

f=open('myfile.txt','w')
for count in  range(5):
      f.write(str(count))
f.close()
f=open('myfile.txt','r')
t=f.read()
print t

Writing and reading string from a file

f=open('myfile.txt','w')
f.write('\n Image Processing Research Group \n www.iprg.co.in \n')
f.close()
f=open('myfile.txt','r')
text=f.read()
print text