如何将单线程代码转换为多线程代码

Question

我遇到一个问题，我将 currentPlace 字符串声明为全局字符串，但我认为如果我在转换为 str 后是正确的，它会覆盖全局设置吗？我一直对此感到茫然。如有任何帮助，我们将不胜感激。

代码：

    from proxy_checker import ProxyChecker
    import json
    import threading
    
    
    
    
    # define an empty list
    places = []
    threads = []
    
    def check():
        global check
        # open file and read the content in a list
        with open('prox_list.txt', 'r') as filehandle:
            for line in filehandle:
            # remove linebreak which is the last character of the string
                global currentPlace
                currentPlace = line[:-1]
            # add item to the list
                places.append(currentPlace)
                checker = ProxyChecker()
                output = checker.check_proxy(str(currentPlace))
                print(str(currentPlace) + " " + str(output))
    
    
        with open('output_prox.txt', 'w') as filehandle:
            json.dump(currentPlace, filehandle)
    
    
    
    for i,link in enumerate(str(currentPlace)):
        t = threading.Thread(target=check, args=(i, link))
        t.start()
        threads.append(t)
    
    for thread in threads:
        thread.join()

Answer 1

您可以使用 multiprocessing.dummy.Pool class 作为 multi-threading 的简单界面。（它被称为“dummy”是因为它不是真正的 multi-processing，它只是存在于同一个模块中。）

编写您的辅助函数，使其接受参数和 returns 它的值（就像您编写任何其他函数一样）并完全避免使用全局变量。使用 Pool#map method 将辅助函数映射到输入值列表：

from multiprocessing.dummy import Pool as ThreadPool
from multiprocessing import cpu_count
from proxy_checker import ProxyChecker

def check(place):
    checker = ProxyChecker()
    output = checker.check_proxy(place)
    return place, output

places = []
with open('prox_list.txt', encoding='utf8') as filehandle:
    for line in filehandle:
        places.append(line[:-1])

pool = ThreadPool(cpu_count())

results = pool.map(check, places)
print(results)

如何将单线程代码转换为多线程代码

How to Convert a Single-Thread Code to a Multi-Threaded one

python-multithreading

python-3.x