Python map()-reduce() 把字符串转换成浮点数

import re
from functools import reduce

s = '1546.322222'
def ss(x):
    sss = s.split('.')
    return sss[x]

def str2num(x):    
    return int(x)


def m():
    L10 = list(map(str2num,ss(0)))
    L01 = list(map(str2num,ss(1)))
    L = reduce(lambda x,y:x*10+y,L10)+reduce(lambda x,y:x*10+y,L01)*0.1**len(L01)
    return L

print(m())

关键是点的判断，用了re。