这里是多线程，有一个简单的例子会很有帮助。您可以运行它并轻松了解多线程在Python中的工作方式。我使用了一个锁来防止访问其他线程，直到前面的线程完成它们的工作。通过使用这行代码，

t锁定=线程。有界信号量（值=4）

您可以一次允许多个进程，并保留将在稍后或完成之前的进程后运行的其余线程。

import threading
import time

#tLock = threading.Lock()
tLock = threading.BoundedSemaphore(value=4)
def timer(name, delay, repeat):
    print  "\r\nTimer: ", name, " Started"
    tLock.acquire()
    print "\r\n", name, " has the acquired the lock"
    while repeat > 0:
        time.sleep(delay)
        print "\r\n", name, ": ", str(time.ctime(time.time()))
        repeat -= 1

    print "\r\n", name, " is releaseing the lock"
    tLock.release()
    print "\r\nTimer: ", name, " Completed"

def Main():
    t1 = threading.Thread(target=timer, args=("Timer1", 2, 5))
    t2 = threading.Thread(target=timer, args=("Timer2", 3, 5))
    t3 = threading.Thread(target=timer, args=("Timer3", 4, 5))
    t4 = threading.Thread(target=timer, args=("Timer4", 5, 5))
    t5 = threading.Thread(target=timer, args=("Timer5", 0.1, 5))

    t1.start()
    t2.start()
    t3.start()
    t4.start()
    t5.start()

    print "\r\nMain Complete"

if __name__ == "__main__":
    Main()

使用线程/多处理的最简单方法是使用更多高级库，如autothread。

import autothread
from time import sleep as heavyworkload

@autothread.multithreaded() # <-- This is all you need to add
def example(x: int, y: int):
    heavyworkload(1)
    return x*y

现在，您可以为函数提供int列表。Autothread将为您处理所有事务，并只提供并行计算的结果。

result = example([1, 2, 3, 4, 5], 10)

Alex Martelli的回答对我有所帮助。不过，这里有一个我认为更有用的修改版本（至少对我来说）。

更新：可在Python 2和Python 3中使用

try:
    # For Python 3
    import queue
    from urllib.request import urlopen
except:
    # For Python 2 
    import Queue as queue
    from urllib2 import urlopen

import threading

worker_data = ['http://google.com', 'http://yahoo.com', 'http://bing.com']

# Load up a queue with your data. This will handle locking
q = queue.Queue()
for url in worker_data:
    q.put(url)

# Define a worker function
def worker(url_queue):
    queue_full = True
    while queue_full:
        try:
            # Get your data off the queue, and do some work
            url = url_queue.get(False)
            data = urlopen(url).read()
            print(len(data))

        except queue.Empty:
            queue_full = False

# Create as many threads as you want
thread_count = 5
for i in range(thread_count):
    t = threading.Thread(target=worker, args = (q,))
    t.start()

大多数文档和教程都使用Python的“线程和队列”模块，对于初学者来说，它们可能会让人不知所措。

也许可以考虑Python 3的concurrent.futures.ThreadPoolExecutor模块。

结合子句和列表理解，这可能是一个真正的魅力。

from concurrent.futures import ThreadPoolExecutor, as_completed

def get_url(url):
    # Your actual program here. Using threading.Lock() if necessary
    return ""

# List of URLs to fetch
urls = ["url1", "url2"]

with ThreadPoolExecutor(max_workers = 5) as executor:

    # Create threads
    futures = {executor.submit(get_url, url) for url in urls}

    # as_completed() gives you the threads once finished
    for f in as_completed(futures):
        # Get the results
        rs = f.result()

借用本文，我们了解了如何在多线程、多处理和异步/异步之间进行选择及其用法。

Python 3有一个新的内置库，以实现并发和并行-concurrent.futures

因此，我将通过一个实验演示如何通过线程池运行四个任务（即.sleep（）方法）：

from concurrent.futures import ThreadPoolExecutor, as_completed
from time import sleep, time

def concurrent(max_worker):
    futures = []
    tic = time()
    with ThreadPoolExecutor(max_workers=max_worker) as executor:
        futures.append(executor.submit(sleep, 2))  # Two seconds sleep
        futures.append(executor.submit(sleep, 1))
        futures.append(executor.submit(sleep, 7))
        futures.append(executor.submit(sleep, 3))
        for future in as_completed(futures):
            if future.result() is not None:
                print(future.result())
    print(f'Total elapsed time by {max_worker} workers:', time()-tic)

concurrent(5)
concurrent(4)
concurrent(3)
concurrent(2)
concurrent(1)

输出：

Total elapsed time by 5 workers: 7.007831811904907
Total elapsed time by 4 workers: 7.007944107055664
Total elapsed time by 3 workers: 7.003149509429932
Total elapsed time by 2 workers: 8.004627466201782
Total elapsed time by 1 workers: 13.013478994369507

[注]：

正如您在上面的结果中看到的，最好的情况是这四项任务有3名员工。如果有进程任务而不是I/O绑定或阻塞（多处理而不是线程），则可以将ThreadPoolExecutor更改为ProcessPoolExecutoor。

这里是使用线程导入CSV的一个非常简单的示例。（图书馆的收录可能因不同的目的而有所不同。）

助手函数：

from threading import Thread
from project import app
import csv


def import_handler(csv_file_name):
    thr = Thread(target=dump_async_csv_data, args=[csv_file_name])
    thr.start()

def dump_async_csv_data(csv_file_name):
    with app.app_context():
        with open(csv_file_name) as File:
            reader = csv.DictReader(File)
            for row in reader:
                # DB operation/query

驾驶员功能：

import_handler(csv_file_name)