[LeetCode&Python] Problem 504. Base 7

Given an integer, return its base 7 string representation.

Example 1:

Input: 100
Output: "202"

Example 2:

Input: -7
Output: "-10"

Note: The input will be in range of [-1e7, 1e7].

class Solution(object):
    def convertToBase7(self, num):
        """
        :type num: int
        :rtype: str
        """
        ans=""
        if num<0:
            neg=True
        else:
            neg=False
        num=abs(num)
        while num>=7:
            ans+=str(num%7)
            num=num//7
        ans+=str(num)
        if neg:
            ans='-'+ans[::-1]
            return ans
        return ans[::-1]