Perimeter and area of a circle and finding Natural Exponential Function

import math
r=int(raw_input('Enter the radius of circle:'))
perimeter=2*math.pi*r
print 'Perimeter of a circle :',perimeter
area=math.pi*(r**2)
print 'Area of acircle :',area

x=int(raw_input('Enter the value of x in y=e**x:'))
y=math.e**x
print 'Natural Exponential Function value :',y

Sorting the numbers in the List

L=int(raw_input("Enter the length of list: "))
p=list()
for i in range(L):
      num=int(raw_input("Enter the elements : "))
      p.append(num)
print '\nUnsorted list is: ',p
for i in range (len(p)):
 for j in range (i+1,len(p)):
  if p[i]>p[j]:
   t=p[i]
   p[i]=p[j]
   p[j]=t
else:
 print '\nSorted List is:' ,p

Search the Element in a list

flag=0
L=int(raw_input("Enter the length of list: "))
p=list()
for i in range(L):
      num=int(raw_input("Enter the elements : "))
      p.append(num)
j=int(raw_input("Enter the element to find: "))
     
for i in range(L):
      if (p[i]==j):
            flag=1
if flag==1:
      print "Element is found"
else:
        print "Element is not found"

Delete Duplicate numbers in a list

l1=list()
l2=list()
w=int(raw_input("Enter the elements in list:"))
for i in range(w):
      n=int(raw_input("Enter the list:"))
      l1.append(n)

for i in l1:
 if i not in l2:
  l2.append(i)
print ' Delete Duplicate numbers in a list: ', l2

Program to check the Perfect Number or Not

num=input("Enter the number:")
i=1
while i<=num/2:
 s=i**2
 if s==num:
  print "perfect square"
  break
 i+=1
else:
 print "Not a perfect square"