Python之str型转成int型

str转int:

 def fn(x,y):
     return x*10+y

 def char2num(s):
     return {'':0, '':1, '':2, '':3, '':4, '':5, '':6, '':7, '':8, '':9}[s]  # 特别注意这里，后面还有个 [s]

 print(type(reduce(fn, map(char2num, ''))))
 print(reduce(fn, map(char2num, '')))

输出如下：

 <type 'int'>
 1738785

整理成一个 str2int 函数就是如下喽：

 from functools import reduce

 def str2int(s):
     def fn(x,y):
         return x*10+y
     def char2num(s):
         return {'':0, '':1, '':2, '':3, '':4, '':5, '':6, '':7, '':8, '':9}[s]
     return reduce(fn,map(char2num,s))

 print(str2int(''))
 print(type(str2int('')))

用匿名函数lambda再简化一下就成了下面这个样子：

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

WOC，就一行代码哦，够简单！