Python多处理队列不共享队列项

Question

我正在创建两个进程。将一个int值添加到一个Mutliprocessing.Queue从1到5.另一个将添加到Queue一次然后它将循环10秒并尝试从队列中读取值。

为什么我的第二个进程在第一个线程中没有将项添加到队列中？我假设在创建Multiprocessing.Queue时，我可以从一个进程添加它，并且它可以被另一个进程读取。看起来它只是添加到传递的Qeueu而不是父队列。我是否可以从父级创建的2个不同进程中将项添加到某种类型的队列？

from multiprocessing import Process, Queue
import time


def f(q):

    for a in range(5):
        print "Adding to Q!"
        time.sleep(1)
        q.put(a)

def g(q):

    i = 0
    v = True
    q.put("Adding to this q")
    while v == True:
        time.sleep(1)
        i = i + 1
        print "Get slept time " , i
        try:
                print "From the q " + str(q.get(True,1))
        except:
                print "Empty"
        if i == 10:
                v = False

if __name__ == '__main__':
    q = Queue(10)
    print "First process"
    p = Process(target=f, args=(q,))
    p.start()

    print "Second Process"
    p1 = Process(target=g, args=(q,))
    p1.start()

    p.join()
    p1.join()

添加或删除join（）似乎对所需的输出

没有影响

我的输出截至目前。 **它不是所需的输出**

First process
Second Process
Adding to Q!
Get slept time  1
From the q Adding to this q
Adding to Q!
Get slept time  2
Adding to Q!
Empty
Get slept time  3
Adding to Q!
Empty
Get slept time  4
Adding to Q!
Empty
Get slept time  5
Empty
Get slept time  6
Empty
Get slept time  7
Empty
Get slept time  8
Empty
Get slept time  9
Empty
Get slept time  10
Empty

Answer 1

好吧，问题不在于队列，
它在你的print "From the q " + q.get(True,1)

中

您的例外是TypeError: cannot concatenate 'str' and 'int' objects

您最好使用print "From the q {}".format(q.get(True,1))

@tiggles     编辑后编辑：
从队列中读/写没有问题。
这里是正常的代码示例：

from multiprocessing import Process, Queue
import time

def f(q):

    for a in range(5):      
        time.sleep(1)
        q.put(a)

def g(q):

    i = 0
    v = True
    q.put("Adding to this q")
    while v == True:
        time.sleep(1)
        i = i + 1
        print "Get slept time " , i
        try:
            print "From the q {}".format(q.get(True,1)) 
        except Exception as e:
            print 'exception raised {} {}'.format(e, type(e))
            print "Empty"
        if i == 10:
            v = False

if __name__ == '__main__':
    q = Queue(10)
    p = Process(target=f, args=(q,))
    p.start()

    p1 = Process(target=g, args=(q,))
    p1.start()

    p.join()
    p1.join()
    print q.qsize(), q.empty()

和结果：

Get slept time  1
From the q Adding to this q
Get slept time  2
From the q 0
Get slept time  3
From the q 1
Get slept time  4
From the q 2
Get slept time  5
From the q 3
Get slept time  6
From the q 4
Get slept time  7
exception raised  <class 'Queue.Empty'>
Empty
Get slept time  8
exception raised  <class 'Queue.Empty'>
Empty
Get slept time  9
exception raised  <class 'Queue.Empty'>
Empty
Get slept time  10
exception raised  <class 'Queue.Empty'>
Empty
0 True

有任何问题吗？