Python从门到精通(六):线程-03-线程间通信（Python线程间通信）

Python从门到精通(六):线程-03-线程间通信（Python线程间通信）

一、共享队列

1.1、​简单队列

from queue import Queuefrom threading import Threaddef producer(out_q): while True: data = 'hello world!' out_q.put(data)def consumer(in_q): while True: data = in_q.get() print(f'get data is: {data}')q = Queue()t1 = Thread(target=consumer, args=(q,))t2 = Thread(target=producer, args=(q,))t1.start()t2.start()

1.2、协调者队列

from queue import Queuefrom threading import Thread_sentinel = object()def producer(out_q): put_time = 0 while True: data = 'hello world!' out_q.put(data) put_time += 1 if put_time == 5: out_q.put(_sentinel)def consumer(in_q): while True: data = in_q.get() print(f'get data is: {data}') if data is _sentinel: in_q.put(_sentinel) breakq = Queue()t1 = Thread(target=consumer, args=(q,))t2 = Thread(target=producer, args=(q,))t1.start()t2.start()

1.3、优先级队列

import heapqimport threadingclass PriorityQueue: def __init__(self): self._queue = [] self._count = 0 self._cv = threading.Condition() def put(self, item, priority): with self._cv: heapq.heappush(self._queue, (-priority, self._count, item)) self._count += 1 self._cv.notify() def get(self): with self._cv: while len(self._queue) == 0: self._cv.wait() return heapq.heappop(self._queue)[-1]

1.4、队列异常

import queueq = queue.Queue()try: data = q.get(block=False)except queue.Empty: ...try: item = '' q.put(item, block=False)except queue.Full: ...try: data = q.get(timeout=5.0)except queue.Empty: ...

二、JOIN方法的使用

from queue import Queuefrom threading import Thread_sentinel = object()def producer(out_q): put_time = 0 while True: data = 'hello world!' out_q.put(data) put_time += 1 if put_time == 5: out_q.put(_sentinel)# A thread that consumes datadef consumer(in_q): while True: data = in_q.get() print(f'get data is: {data}') if data is _sentinel: in_q.put(_sentinel) break in_q.task_done()q = Queue()t1 = Thread(target=consumer, args=(q,))t2 = Thread(target=producer, args=(q,))t1.start()t2.start()q.join()

三、线程监听

from queue import Queuefrom threading import Thread, Event# A thread that produces datadef producer(out_q): while True: # Produce some data ... # Make an (data, event) pair and hand it to the consumer evt = Event() data = '' out_q.put((data, evt)) ... # Wait for the consumer to process the item evt.wait()def consumer(in_q): while True: data, evt = in_q.get() # Process the data ... # Indicate completion evt.set()

四、线程间复制

from queue import Queuefrom threading import Threadimport copy# A thread that produces datadef producer(out_q): while True: # Produce some data ... data = '' out_q.put(copy.deepcopy(data))# A thread that consumes datadef consumer(in_q): while True: # Get some data data = in_q.get() # Process the data ...

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