每日一题之LeetCode 171excel表列序号

class Solution:
def titleToNumber(self, s):
"""
:type s: str
:rtype: int
"""
sum=0
dict1={'A':1,'B':2,'C':3,'D':4,'E':5,'F':6,'J':7,'H':8,'I':9,'G':10,'K':11,'L':12,'M':13,'N':14,'O':15,'P':16,'Q':17,'R':18,'S':19,'T':20,'U':21,'V':22,'W':23,'X':24,'Y':25,'Z':26,}
for i in range(0,len(s)):
sum=sum+dict1[s[i]]*26**(len(s)-i-1)
return sum

t=Solution()
print(t.titleToNumber('ZY'))

#第二种
sum = 0
for c in s:
sum = sum*26 + ord(c) - 64 # 64 = ord('A') - 1
return sum

chr()函数用一个范围在range（256）内的（就是0～255）整数作参数，返回一个对应的字符。
unichr()跟它一样，只不过返回的是Unicode字符。
ord（）函数是取出来一个字符对用的ASCII数值。