Python之str型转成int型

Posted 2020-09-28

str转int:

1 def fn(x,y):
2     return x*10+y
3 
4 def char2num(s):
5     return {‘0‘:0, ‘1‘:1, ‘2‘:2, ‘3‘:3, ‘4‘:4, ‘5‘:5, ‘6‘:6, ‘7‘:7, ‘8‘:8, ‘9‘:9}[s]  # 特别注意这里，后面还有个 [s]
6 
7 print(type(reduce(fn, map(char2num, ‘1738785‘))))
8 print(reduce(fn, map(char2num, ‘1738785‘)))

输出如下：

1 <type ‘int‘>
2 1738785

整理成一个 str2int 函数就是如下喽：

 1 from functools import reduce
 2 
 3 def str2int(s):
 4     def fn(x,y):
 5         return x*10+y
 6     def char2num(s):
 7         return {‘0‘:0, ‘1‘:1, ‘2‘:2, ‘3‘:3, ‘4‘:4, ‘5‘:5, ‘6‘:6, ‘7‘:7, ‘8‘:8, ‘9‘:9}[s]
 8     return reduce(fn,map(char2num,s))
 9 
10 print(str2int(‘365779‘))
11 print(type(str2int(‘365779‘)))

 

用匿名函数lambda再简化一下就成了下面这个样子：

1 def str2int(s):
2     return reduce(lambda x,y:x*10+y, map(lambda s:{‘0‘:0, ‘1‘:1, ‘2‘:2, ‘3‘:3, ‘4‘:4, ‘5‘:5, ‘6‘:6, ‘7‘:7, ‘8‘:8, ‘9‘:9}[s], s))

WOC，就一行代码哦，够简单！