python 用递归实现 数字组成的str转int

Question

代码如下

def strToInt(s):
    result =0
    if(len(s) == 1):
        return int(s)
    else:
        start = int(s[0:1])
        result = (result+start)*10+strToInt(s[1:])
        return result

print(strToInt('781'))

运行结果不如人意：151 ，应该是781呀
百思不得其解

Answer 1

def change(s):
    if len(s) == 1:
        return int(s)
    res = int(s[0]) * (10 ** (len(s)-1)) + change(s[1:])
  
    return res
change('781')