我也剛看,試了好久,初步知道怎么回事了.
先回答你的兩個問題:
1、setDaemon所綁定的都是主線程,都是一樣的,即運行py文件第一次創(chuàng)建的那個線程(也是主進程),有且只有一個
2、queue.join()如果單獨使用會被無限掛起,字面翻譯為等待隊列為空，再執(zhí)行別的操作.但是他等待的隊列不是我們創(chuàng)建的aqueue,而是一個與aqueue長度相等的一個"需要完成的子線程"隊列,他判斷的很可能是這個列表,當這個列表為空時queue.join()才成立,所以如樓上的那位所說queue.join()要結合aqueue.task_done()函數(shù)來使用,aqueue.task_done()的意思是每task_done一次 就從"需要完成的子線程"隊列里刪掉一個元素，這樣在最后join的時候根據(jù)隊列長度是否為零來判斷隊列是否結束,aqueue.task_done()用在子線程函數(shù)中,這樣queue.join()才知道完成了多少個子線程,才不會無限掛起,也就是為什么你沒退出的原因

但是你的程序也有問題:
主要的問題是,守護線程機制:主線程運行完畢去結束子線程時,由于有大量的子線程還在time.sleep(5),結束這些子線程會觸發(fā)異常:

Fatal Python error: could not acquire lock for <_io.BufferedWriter name='<stdout>'> at interpreter shutdown, possibly due to daemon threads

Thread 0x000019cc (most recent call first):
  File "test.py", line 13 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

這是因為:
下面的一些說法是錯誤的,可以看我后面的補充,這里就不改了,是一種猜測,但是應該確實不是這樣
喂不飽的子線程:你aqueue.put(i)了是10個元素,但是卻運行了20個子線程來"吃"這10個元素,又因為這20個線程都是守護進程,當10個吃飽了,這個10個卡在了item = aqueue.get()等待接受元素,另外的那些很有可能卡在了time.sleep(5)上,而主線程運行完畢,準備結束所有的守護進程,我判斷,結束卡在item = aqueue.get()的守護進程不會報錯,而結束其他程序,如time.sleep會觸發(fā)異常,這也是為啥樓上那位吧你的for i in range(20):改成了for i in range(1):的原因.

還有兩種退出的方式:
1、是在子線程里判斷隊列是否為空:

if aqueue.empty() == True:
    break

為空就退出
2、主線程通過queue向子線程發(fā)送退出命令
其實這里一般用pipe管道的，Queue隊列不好針對特定的線程進行退出操作，大概的偽碼為：

主線程:

aqueue.put('quit')

子線程""

item = aqueue.get()
if item == 'quit':
    return
else:
    # "do something"

所以多進程,多線程還是要控制好程序邏輯,控制好調度.

我沒用過守護進程,我一般用的是普通的用戶進程,這樣主線程跑完會等待所有子線程運行完畢再結束

其實還沒完=_=:
后面的都是我的猜測,算是附加的,選修:
這程序的細節(jié)也值得我們關注:
這程序如果真去實踐的話很容易炸,以下都是我的猜測
如上所述,我們修改程序,注意注釋

import queue
import threading
import time

aqueue = queue.Queue()
# 發(fā)送了0到9的十個數(shù)據(jù)
for i in range(10):
    aqueue.put(i)

def worker():
    while True:
        # 輸出當前線程,和主線程(可以看到主線程都一樣)
        print('thread %s is running...\nmain_thread %s is running...\n\n' % (threading.current_thread().name,threading.main_thread()))
        time.sleep(1)
        item = aqueue.get()
        print(item)
        aqueue.task_done()
        print('thread end')


n = 1
"""注意這!!!!!!!!!!!!!!!!!!"""
# 運行了10個線程來處理這十個數(shù)據(jù)
for i in range(10):
    print("run thread Counts: ",n)
    n += 1
    a = threading.Thread(target = worker)
    a.setDaemon(True)
    a.start()

aqueue.join()
print('after to do')
print('end')

10個數(shù)據(jù)10個線程,time.cleep(5)秒結果會怎么樣?運行正常?
很不幸運的炸了23333333
有一定的幾率報錯,和上面一樣:

Fatal Python error: could not acquire lock for <_io.BufferedWriter name='<stdout>'> at interpreter shutdown, possibly due to daemon threads

Thread 0x0000063c (most recent call first):
  File "test.py", line 13 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

我電腦上大部分運行正常,只有幾次會這樣,為什么會這樣?
換成10個數(shù)據(jù)9個線程就不會出錯了
我猜測的情況是,初步認為:
直接看完整的輸出,注意看有注釋的地方:

run thread Counts:  1
thread Thread-1 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

run thread Counts:  2

thread Thread-2 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

run thread Counts:  3

thread Thread-3 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

run thread Counts:  4

thread Thread-4 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

run thread Counts:  5

thread Thread-5 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

run thread Counts:  6

thread Thread-6 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

run thread Counts:  7

thread Thread-7 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

run thread Counts:  8

thread Thread-8 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

run thread Counts:  9

thread Thread-9 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

run thread Counts:  10

thread Thread-10 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...


0
1
3
4
thread end
thread end
5
2
thread Thread-2 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

thread end
thread end
thread end
thread Thread-3 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

thread end

thread Thread-4 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

thread Thread-1 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

thread Thread-5 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...





6
8
thread Thread-6 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

thread end
thread end

thread Thread-7 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

7
9
thread Thread-9 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...
"""到這里主線程已經(jīng)完畢"""
thread end
after to do
"""
這里其實系統(tǒng)在調用守護線程的結束程序來結束所有子線程
"""
"""但是在結束守護進程程序后,又運行了一個不該運行的子線程,這就是為什么會報錯的原因"""
thread Thread-10 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

end
thread end


thread Thread-8 is running...
main_thread <_MainThread(MainThread, started 6680)> is running...

Fatal Python error: could not acquire lock for <_io.BufferedWriter name='<stdout>'> at interpreter shutdown, possibly due to daemon threads

Thread 0x00000424 (most recent call first):
  File "test.py", line 14 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

Thread 0x00000f04 (most recent call first):
  File "test.py", line 14 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

Thread 0x0000165c (most recent call first):
  File "test.py", line 13 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

Thread 0x000018b0 (most recent call first):
  File "test.py", line 14 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

Thread 0x00000db4 (most recent call first):
  File "test.py", line 14 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

Thread 0x00001a88 (most recent call first):
  File "test.py", line 14 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

Thread 0x0000111c (most recent call first):
  File "test.py", line 14 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

Thread 0x0000177c (most recent call first):
  File "test.py", line 14 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

Thread 0x000008e4 (most recent call first):
  File "test.py", line 14 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

Thread 0x00001788 (most recent call first):
  File "test.py", line 14 in worker
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 864 in run
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 916 in _bootstrap_inner
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\threading.py", line 884 in _bootstrap

Current thread 0x00001a18 (most recent call first):

看主要的幾句

"""到這里主線程已經(jīng)完畢"""
    thread end
    after to do
    """
    這里其實系統(tǒng)在調用守護線程的結束程序來結束所有子線程
    """
    """但是在結束守護進程程序后,又運行了一個不該運行的子線程,這就是為什么會報錯的原因"""
    thread Thread-10 is running...
    main_thread <_MainThread(MainThread, started 6680)> is running...
    
    end
    thread end

先這樣吧,可以自己運行下程序看看

看了另一個答主的,使用了a.join()也是一種選擇

改成發(fā)送10個數(shù)據(jù),用9個線程跑,效率是最高的(理論)

import queue
import threading
import time

aqueue = queue.Queue()
# 發(fā)送了0到9的十個數(shù)據(jù)
for i in range(10):
    aqueue.put(i)

def worker():
    while True:
        # 輸出當前線程,和主線程(可以看到主線程都一樣)
        print('thread %s is running...\nmain_thread %s is running...\n\n' % (threading.current_thread().name,threading.main_thread()))
        time.sleep(5)
        item = aqueue.get()
        print(item)
        aqueue.task_done()
        print('thread end')


n = 1
"""注意這!!!!!!!!!!!!!!!!!!"""
for i in range(9):
    print("run thread Counts: ",n)
    n += 1
    a = threading.Thread(target = worker)
    a.setDaemon(True)
    a.start()

aqueue.join()
print('after to do')
print('end')

第一個問題 一樣的
第二個問題
1、隊列只有十個值，你開了20個線程，aqueue.get()在取不到值的時候會使線程暫停，后面的線程取不到值程序當然不會退出。
2、while True:也會使線程不停止。
3、aqueue.join()會優(yōu)先于線程執(zhí)行，并阻塞主進程繼續(xù)

如果你是想主進程等待線程結束再停止可以這么寫

import queue
import threading
import time

aqueue = queue.Queue()
for i in range(10):
    aqueue.put(i)


def worker():

    time.sleep(5)
    item = aqueue.get()
    print(item)


for i in range(20):
    a = threading.Thread(target=worker)
    a.setDaemon(True)
    a.start()
    
    a.join()

# aqueue.join()

import Queue
import threading
import time

aqueue = Queue.Queue()
for i in range(10):
    aqueue.put(i)

def worker():
    while True:
        time.sleep(1)
        item = aqueue.get()
        print(item)
        aqueue.task_done()

for i in range(1):
    a = threading.Thread(target = worker)
    a.setDaemon(True)
    a.start()

aqueue.join()
print 'the main thread is already over'

用 aqueue.task_done() 去通知阻塞的 join 是一種方法