Convert a Number to Hexadecimal.py

'''
Given an integer, write an algorithm to convert it to hexadecimal. For negative integer, two’s complement method is used.

Note:

All letters in hexadecimal (a-f) must be in lowercase.
The hexadecimal string must not contain extra leading 0s. If the number is zero, it is represented by a single zero character '0'; otherwise, the first character in the hexadecimal string will not be the zero character.
The given number is guaranteed to fit within the range of a 32-bit signed integer.
You must not use any method provided by the library which converts/formats the number to hex directly.
Example 1:

Input:
26

Output:
"1a"
Example 2:

Input:
-1

Output:
"ffffffff"
'''

class Solution(object):
    def toHex(self, num):
        """
        :type num: int
        :rtype: str
        """
        
        if num == 0:
            return '0'
        
        res = ''
        while num != 0 and len(res) < 8:
            digit = num % 16
            if digit < 10:
                res = str(digit) + res
            else:
                res = chr(ord('a') + digit - 10) + res
                
            num //= 16
            
        return res