# [LeetCode]#504. Base 7

**Environment: Python 3.7**

**Key technique:** divmod function

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].

**Analysis:**

Use divmod function to find quotient and remainder dividing by 7. The 10 Base convert to 7 Base number is as below.

Therefore, the process example is as below.

We also need consider negative case.

**Solution:**

`class Solution(object):`

def convertToBase7(self, num):

ans = ''

if num == 0:

return '0'

neg = False

if num < 0:

num = abs(num)

neg = True

c = 0

while num:

num, c = divmod(num, 7)

ans = str(c) + ans

if neg is True:

return '-' + ans

return ans

**Reference:**