您可能想要使用multiprocessing.Queue
,您可以在其中轉儲對象而不用擔心類型。它也是線程安全的和流程安全的。
下面是一個簡單的隊列示例,用於簡化生產者 - 消費者問題(original source,比薩餅對我有點幫助)。
from multiprocessing import Process, Queue
class Pizza(object):
def __init__(self, pizza_num):
self.pizza_num = pizza_num
self.num_slices = 8
sentinel = "NO PIZZA"
def producer(initial_num_pizzas, total_num_pizzas, q):
"""Cooks Pizzas to be consumed and waits for the consumer to finish eating."""
print("Producer: I am cooking %s Pizzas and putting them on the Queue!"%(total_num_pizzas-initial_num_pizzas))
for i in range(q.qsize(), total_num_pizzas):
print("Producer: Behold, for I have cooked Pizza no. %s"%i)
q.put(Pizza(i))
q.put(sentinel)
def consumer(q):
"""Consumes some Pizza. In this case, all it does is set the number of slices to 0."""
while True:
pizza = q.get()
pizza.num_slices = 0
if pizza == sentinel:
break
print("Comsumer: Pizza no. %s was found! It has %s slices, yum!"%(pizza.pizza_num, pizza.num_slices))
if __name__ == '__main__':
q = Queue()
total_num_pizzas = 10
initial_num_pizzas = 4
## Let's add some Pizzas beforehand:
for i in range(0, initial_num_pizzas):
q.put(Pizza(i))
print("Main: I have precooked %s Pizzas."%q.qsize())
producer_proc = Process(target=producer, args=(initial_num_pizzas, total_num_pizzas, q))
consumer_proc = Process(target=consumer, args=(q,))
producer_proc.start()
consumer_proc.start()
q.close() ## Shop is closed, no more Pizzas will be added to Queue!
q.join_thread()
producer_proc.join()
consumer_proc.join()
下面是一個輸出示例。如果運行它,生產者和消費者打印語句可能會以不同方式進行交錯,因爲並行進程的非確定性執行。
Main: I have precooked 4 Pizzas.
Producer: I am cooking 6 Pizzas and putting them on the Queue!
Producer: Behold, for I have cooked Pizza no. 4
Producer: Behold, for I have cooked Pizza no. 5
Producer: Behold, for I have cooked Pizza no. 6
Producer: Behold, for I have cooked Pizza no. 7
Comsumer: Pizza no. 0 was found! It has 8 slices, yum!
Comsumer: Pizza no. 1 was found! It has 8 slices, yum!
Producer: Behold, for I have cooked Pizza no. 8
Comsumer: Pizza no. 2 was found! It has 8 slices, yum!
Producer: Behold, for I have cooked Pizza no. 9
Comsumer: Pizza no. 3 was found! It has 8 slices, yum!
Comsumer: Pizza no. 4 was found! It has 8 slices, yum!
Comsumer: Pizza no. 5 was found! It has 8 slices, yum!
Comsumer: Pizza no. 6 was found! It has 8 slices, yum!
Comsumer: Pizza no. 7 was found! It has 8 slices, yum!
Comsumer: Pizza no. 8 was found! It has 8 slices, yum!
Comsumer: Pizza no. 9 was found! It has 8 slices, yum!
請注意,您應該use Sentinels to mark the end of your Queue。我在這裏使用了「NO PIZZA」,但他們可以做任何事情。
實際上,使用Array和RawArray(在多處理中)是一種在內存中創建共享數組以供多個進程訪問的方法。我可以寫上面的代碼讓我們說一個共享的整數數組,但是有問題寫它的一組對象。例如,如果我寫: >>> import multiprocessing as mp >>> import numpy as np >>> sh = mp.RawArray(ctypes.c_int,10) >>> f = np.frombuffer(sh, dtype = int) >>> f [0] = 1 >>> sh [0] 它完美地工作! – user823743 2014-11-07 15:13:53
@ user823743正確,但你不能用指針做同樣的事情。 – 2014-11-07 18:04:19
你是對的;幸運的是,我發現了另一種避免多處理的方法。謝謝。 – user823743 2014-11-08 19:24:27