python实习总结(yeild,async,azwait和协程)

def fab(max): 
    n, a, b = 0, 0, 1 
    while n < max: 
        yield b      # 使用 yield
        # print b 
        a, b = b, a + b 
        n = n + 1
for n in fab(5): 
    print n

>>>import types 
>>> isinstance(fab, types.GeneratorType) 
False 
>>> isinstance(fab(5), types.GeneratorType) 
True

>>>from collections import Iterable 
>>> isinstance(fab, Iterable) 
False 
>>> isinstance(fab(5), Iterable) 
True

def read_file(fpath): 
    BLOCK_SIZE = 1024 
    with open(fpath, 'rb') as f: 
        while True: 
            block = f.read(BLOCK_SIZE) 
            if block: 
                yield block 
            else: 
                return

async def func1(num):
    print('--func1 start--')
    await asyncio.sleep(num)
    print('--func1 done--')
    return 'func1 ok'
async def func2(num):
    print('--func2 start--')
    await asyncio.sleep(num)
    print('--func2 done--')
    return 'func2 ok'
async def main():
    task1 = asyncio.ensure_future(func1(3))
    task2 = asyncio.ensure_future(func2(5))
    tasks = [task1, task2]
    res = await asyncio.gather(*tasks)
    return res
    # done, pending = await asyncio.wait(tasks)
    # for t in done:
    #     print(t.result())
    # print(done)
    # print(pending)
if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    result = loop.run_until_complete(main())
    print(result)
```python
--func1 start--
--func2 start--
--func1 done--
--func2 done--
['func1 ok', 'func2 ok']

>>> def simple_corotine():
...     print('---->coroutine started')
...     x = yield　　#有接收值，所以同生成器一样，需要先激活,使用next
...     print('---->coroutine recvied:',x)
...
>>> my_coro = simple_corotine()
>>> my_coro
<generator object simple_corotine at 0x0000000000A8A518>

>>> next(my_coro)　　#先激活生成器，执行到yield val语句　　#或者使用send(None)也可以激活生成器
---->coroutine started
>>> my_coro.send(24)　　#向其中传入值，x = yield
---->coroutine recvied: 24
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
StopIteration　　#当生成器执行完毕时会报错

>>> def averager():
...     total = 0.0
...     count = 0
...     aver = None
...     while True:
...             term = yield aver
...             total += term
...             count += 1
...             aver = total/count
...
>>> coro_avg = averager()
>>> coro_avg.send(None)
>>> coro_avg.send(10)
10.0
>>> coro_avg.send(20)
15.0
>>> coro_avg.send(30)
20.0
>>> coro_avg.send(40)
25.0

>>> def coro_active(func):
...     def inner(*args,**kwargs):
...         gen = func(*args,**kwargs)
...         next(gen)   #gen.send(None)
...         return gen
...     return inner
...
>>> @coro_active
... def averager():
...     total = 0.0
...     count = 0
...     aver = None
...     while True:
...             term = yield aver
...             total += term
...             count += 1
...             aver = total/count
...
>>> coro_avg = averager()
>>> coro_avg.send(10) 10.0 >>> coro_avg.send(20) 15.0 >>> coro_avg.send(30) 20.0