Python生成器generator用法示例

l = [x * 2 for x in range(10)] # 列表生成式
g = (x * 2 for x in range(10))
print(l,g) # l打印的是一个列表，g则是一个generator的内存地址

for index in g:
  print(index)

print(g.__next__())   # 0
print(g.__next__())   # 2
print(g.__next__())   # 4
print(g.__next__())   # 6
print(g.__next__())   # 8

def fib(num):
  n = 0
  while n < num:
    print(n)
    n+=1
fib(50)

def fib(num):
  n = 0
  while n < num:
    yield n   # 在使用yield关键字时，需在前面先定义一个变量n
    n+=1
g = fib(50)   # 此时的g是一个generator

def fib():
  print("step 1")
  yield 1
  print("step 2")
  yield 2
  print("step 3")
  yield 3
g = fib()
g.__next__()  # 结果：step 1
g.__next__()  # 结果：step 2
g.__next__()  # 结果：step 3

# -* coding:utf-8 -*-
#! python3
'''
Created on 2018年8月10日

@author: Administrator
'''
def fib(num):
  n = 0
  while n < num :
    yield n
    n+=1
g = fib(10)
while True:
  print(g.__next__())

def fib(num):
  n = 0
  while n < num :
    yield n
    n+=1
g = fib(10)
while True:
  try:
    print(g.__next__())
  except StopIteration:
    print("已经完毕")
    break

# -*- coding:utf-8 -*-
#! python3
'''
Created on 2018年8月10日

@author: Administrator
'''
import time
def startEat(name):
  print("%s准备开始吃包子了"%name)
  while True:
    b = yield
    print("%s被%s吃了"%(b,name))
def startMake():
  laowang = startEat("laowang")
  laowang.__next__()
  for index in range(10):
    time.sleep(1)
    print("已经做好了包子%d号"%index)
    laowang.send("包子%d号"%index)
startMake()