【LEETCODE】171-Excel Sheet Column Number

Related to question
Excel Sheet Column Title
Given a column title as appear in an Excel sheet, return its corresponding column number.
For example:
A -> 1
B -> 2
C -> 3
...
Z -> 26
AA -> 27
AB -> 28

26进制转10进制

class Solution(object):
def titleToNumber(self, s):
"""
:type s: str
:rtype: int
"""
r=0

for i in range(len(s)):
r=r*26
r=r+ord(s[i])-64

return r