In [10]:

    

def averager():
    total = 0.0
    count = 0
    average = None
    
    while True:
        d = yield average
        total +=d
        count += 1
        average = total / count


    

In [11]:

    

cor_avg = averager()


    

In [12]:

    

next(cor_avg)


    

In [14]:

    

cor_avg.send(12)


    

    
Out[14]:





11.5

In [17]:

    

from inspect import getgeneratorstate


    

In [21]:

    

from functools import wraps

def coroutine(func):
    @wraps(func)
    def primer(*args, **kwargs):
        gen = func(*args, **kwargs)
        next(gen)
        return gen
    
    return primer


    

In [16]:

    

coro_avg = averager()


    

In [18]:

    

getgeneratorstate(coro_avg)


    

    
Out[18]:





'GEN_CREATED'

In [23]:

    

@coroutine
def averager():
    total = 0.0
    count = 0
    average = None
    
    while True:
        d = yield average
        total +=d
        count += 1
        average = total / count


    

In [24]:

    

coro_avg = averager()


    

In [25]:

    

getgeneratorstate(coro_avg)


    

    
Out[25]:





'GEN_SUSPENDED'

In [26]:

    

coro_avg.send(40)


    

    
Out[26]:





40.0

In [27]:

    

coro_avg.send(10)


    

    
Out[27]:





25.0

In [28]:

    

coro_avg.send('spam')


    

    




---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-28-ab30dc25c38f> in <module>()
----> 1 coro_avg.send('spam')

<ipython-input-23-ed0a49874358> in averager()
      7     while True:
      8         d = yield average
----> 9         total +=d
     10         count += 1
     11         average = total / count

TypeError: unsupported operand type(s) for +=: 'float' and 'str'

In [29]:

    

coro_avg.send(15)


    

    




---------------------------------------------------------------------------
StopIteration                             Traceback (most recent call last)
<ipython-input-29-7c83c48f0082> in <module>()
----> 1 coro_avg.send(15)

StopIteration: 

In [33]:

    

class DemoException(Exception):
    """"""
def demo_exc_handling():
    print("-> coroutine started")
    while True:
        try:
            x = yield
        except DemoException: #<1>
            print('*** DemoException handled.')
        else:
            print("-> coroutine received: {!r}".format(x))
    raise RuntimeError('This line should never run.')


    

In [34]:

    

exc_coro = demo_exc_handling()


    

In [35]:

    

next(exc_coro)


    

    




-> coroutine started

In [37]:

    

exc_coro.send(11)


    

    




-> coroutine received: 11

In [38]:

    

exc_coro.send(11)


    

    




-> coroutine received: 11

In [40]:

    

exc_coro.throw(DemoException)


    

    




*** DemoException handled.

In [41]:

    

getgeneratorstate(exc_coro)


    

    
Out[41]:





'GEN_SUSPENDED'

In [ ]:

    




    

In [34]:

    

exc_coro = demo_exc_handling()


    

In [35]:

    

next(exc_coro)


    

    




-> coroutine started

In [37]:

    

exc_coro.send(11)


    

    




-> coroutine received: 11

In [42]:

    

exc_coro.throw(ZeroDivisionError)


    

    




---------------------------------------------------------------------------
ZeroDivisionError                         Traceback (most recent call last)
<ipython-input-42-d0a75d13dc38> in <module>()
----> 1 exc_coro.throw(ZeroDivisionError)

<ipython-input-33-0a06ddc6e361> in demo_exc_handling()
      5     while True:
      6         try:
----> 7             x = yield
      8         except DemoException: #<1>
      9             print('*** DemoException handled.')

ZeroDivisionError: 

In [43]:

    

getgeneratorstate(exc_coro)


    

    
Out[43]:





'GEN_CLOSED'

In [ ]:

    




    

In [46]:

    

class DemoException(Exception):
    """"""
def demo_finally():
    print("-> coroutine started")
    try:
        while True:
            try:
                x = yield
            except DemoException:
                print("*** DemoException handled. Continuing...")
            else:
                print("->coroutine received: {!r}".format(x))
    finally:
        print("-> coroutine ending")


    

In [57]:

    

fin_coro = demo_finally()


    

In [58]:

    

next(fin_coro)


    

    




-> coroutine started

In [59]:

    

fin_coro.send(11)


    

    




->coroutine received: 11

In [60]:

    

fin_coro.send(12)


    

    




->coroutine received: 12

In [61]:

    

fin_coro.send("spam")


    

    




->coroutine received: 'spam'

In [56]:

    

fin_coro.throw(ZeroDivisionError)


    

    




-> coroutine ending






    




---------------------------------------------------------------------------
ZeroDivisionError                         Traceback (most recent call last)
<ipython-input-56-d0ec4ddb0825> in <module>()
----> 1 fin_coro.throw(ZeroDivisionError)

<ipython-input-46-8c33fb2f1f1e> in demo_finally()
      6         while True:
      7             try:
----> 8                 x = yield
      9             except DemoException:
     10                 print("*** DemoException handled. Continuing...")

ZeroDivisionError: 

In [ ]:

    




    

In [62]:

    

from collections import namedtuple


    

In [64]:

    

Result = namedtuple('Result', 'count average')


    

In [65]:

    

def averager():
    total = 0.0
    count = 0
    average = None
    
    while True:
        term = yield
        if term is None:
            break
        total += term
        count += 1
        average = total/count
    return Result(count, average)


    

In [66]:

    

coro_avg = averager()


    

In [67]:

    

next(coro_avg)


    

In [68]:

    

coro_avg.send(10)


    

In [69]:

    

coro_avg.send(20)


    

In [70]:

    

coro_avg.send(None)


    

    




---------------------------------------------------------------------------
StopIteration                             Traceback (most recent call last)
<ipython-input-70-a9c80bbec98f> in <module>()
----> 1 coro_avg.send(None)

StopIteration: Result(count=2, average=15.0)

In [ ]: