Using Python, reverse an integer, and tell if pali

Question

Using Python, reverse an integer and determine if it is a palindrome. Here is my definition of reverse and palindrome. Do I have a correct logic?

def reverse(num):
    s=len(num)
    newnum=[None]*length
    for i in num:
        s=s-1
        newnum[s]=i
        return newnum

def palindrome(num):
    a=str(num)
    l=len(z)/2
    if a[:1]==a[-1:][::-1]:
        b=True
    else:
        b=False

I am having some trouble to write def main.

Answer 1

def palindrome(num):
    return str(num) == str(num)[::-1]

Answer 2

This code converts int to String and then checks if the string is pallindrome. The advantage is that it is fast, the disadvantage being that it converts int to String thereby compromising with the perfect solution to question.

It handles negative int as well.

class Solution:
    def isPalindrome(self, x):
        """
        :type x: int
        :rtype: bool
        """
        s = str(x)
        if x >=0 :
            if s == s[::-1]:
                return True
            else:
                return False
        else:
            return False

Answer 3

import math

a = raw_input("Enter number:")
n = -1

reverse = 0    
for i in a:
        n += 1
        digit = math.pow(10,n)
        reverse = int(i)*digit + reverse

print int(reverse)  

if int(reverse) == int(a):
        print "Palindrome"
else:
        print ":("

Answer 4

def revers(num): 
  rev = 0    
  while(num > 0):    
      rem = num %10    
      rev = (rev *10) + rem    
      num = num //10    

  return num