# -*- coding: utf-8 -*-

def f(x):

return x * x

def fn(x,y):

return x *10 + y

def char2num(s):

return {'0': 0,'1':1,'2':2,'3':3,'4':4,'5':5,'6':6,'7':7,'8':8,'9':9}[s]

def tolower(s):

return s.lower()

def is_odd(n):

return n % 2 == 1

# 产生奇数列

def _odd_iter():

n =1

while True:

n = n+2

yield n

# 筛选函数

def _not_divisible(n):

return lambda x : x %n >0

def primes():

yield 2

it = _odd_iter()

while True:

n =next(it)

yield n

it = filter(_not_divisible(n),it)

if __name__ =='__main__':

# map 函数 接收两个参数，一个是函数，一个是Iterable ,map 讲传入的函数依次作用到序列的每个元素，并作为新的Iterator 返回

m =map(f,[1,2,3,4,5,6,7,8,9])

list(m)

# filter()把传入的函数一次作用于每个元素，然后根据返回值是True还是False决定保留还是丢弃该元素

r = reduce(fn,map(char2num,'13579'))

print r

L1 =['adam','LISA','barT']

L2=map(tolower,L1)

print list(L2)

L3 =list(filter(is_odd,[1,2,3,4,5,6,9,10,15]))

print L3

for n in primes():

if n<100:

print n

else:

break