python3-cookbook/basic/myfunc/myyield.py at master · pythoningLearning/python3-cookbook

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# encoding: utf-8

"""

Topic: sample

Desc :

Python生成器：生成器是一个带有yield语句的函数。

一个生成器能暂停并返回一个中间结果，返回这个值给调用者并暂停执行。

当生产器的next()方法被调用时，它会准确的从离开的那个地方继续

"""

from random import randint

__author__ = 'Xiong Neng'

# 生成器函数定义

def simpleGen():

yield 1

yield '2--->punch'

def gendemo():

print(simpleGen().__next__())

# 生成器对象的获取

a = simpleGen()

print(a.__next__())

# Python的for循环有next()调用和对StopIteration的处理

# 天生就是使用生成器的好手段

for eachItem in simpleGen():

print(eachItem)

# 序列的随机迭代器 pop index out of range ？？？？？？

def randGen(alist):

while len(alist) > 0:

yield alist.pop(randint(0, len(alist)))

def counter(start_at=0):

print('new start...%d' % (start_at,))

count = start_at

while True:

val = (yield count)

print('count=%s, val=%s' % (count, val,))

if val is not None:

count = val

else:

count += 1

if __name__ == '__main__':

count = counter(5)

print(count.__next__())

print(count.send(99))

print(count.__next__())

count.close()

# print(count.next()) # ERROR

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