Factorial using while loop

f=i=1
n=int(raw_input('Enter the number: '))
while i<=n:
      f=f*i
      i=i+1
print f

To check the number is Prime or Not

n=int(raw_input('Enter the number to check:'))
flag=0
i=2
while(i<=(n/2)):
    if (n%i==0):
        flag=1
    i=i+1
if(flag==0):
    print  'The number ',n, ' is prime number'
else:
    print 'The number ',n, ' is not prime number'

Factorial using Recursion

def recur_factorial(n):
   if n == 1:
       return n
   else:
       return n*recur_factorial(n-1)


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

if num < 0:
   print("Sorry, factorial does not exist for negative numbers")
elif num == 0:
   print("The factorial of 0 is 1")
else:
   print("The factorial of",num,"is",recur_factorial(num))

Searching the character count from string

word = raw_input('Enter the String:')
char = raw_input('Enter the Character to search:')

count = 0
for letter in word:
 if letter == char:
  count = count + 1
print 'Number of times repeated:', count

Basic String Manipulations

word = 'banana talks'

for i in word:  #Here the i is the letters in the string word
      print 'Character from string:',i

for h in range(len(word)):   #Here the h is index created by range function with value created by length
      print 'Index:',h,'charater:' ,word[h]

n1 = word.upper()

print 'String in the upper case:', n1

n2 = word.lower()

print 'String in the lower case:', n2

print 'Display a part of string :',word[1:5] # It display string from index 1 to 4

print 'Display a part of string :',word[4:8] # It display string from index 4 to 7

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