Multiprocessing concurrent.futures 不更新全局字典和列表

Question

我需要你的多处理帮助来更新全局字典数据。 我使用了两个函数，第一个函数是在 for 循环中进行多处理。 第二个功能是更新全局字典数据。 多重处理后，所有数据都没有更新。

这是我的示例代码：

import concurrent.futures
from multiprocessing import Process
from multiprocessing import Manager


list_key = ['A','B','C','D','E','F','G','H','I','K']

# first function. increase the value in Dict_value
def first(x,y):
    
    print('Call Increase Value Function')

    print(x)
    print(y[x])
    y[x] += 1
    print(y[x])

    print('Finished Increase Value')

# second function. square the value in the Dict_value
def second(x,y): 
    
    
    print('Call sqrt_dict_value function')

    print(y)
    for i in x:
        y[i] =  y[i]* y[i]
        print(y[i])
    print('Finished sqrt_dict_value')


def main():

    # declare the list and dict
    with Manager() as manager :
        dict_value = manager.dict()
        list_key = manager.list()
        list_key = ['A','B','C','D','E','F','G','H','I','K']
        dict_value = {'A':0,'B':1,'C':2,'D':3,'E':4,'F':5,'G':6,'H':7,'I':8,'K':9}

        # multiprocessing for first function.
        with concurrent.futures.ProcessPoolExecutor(max_workers=2) as executor:
            process = executor.submit(first,list_key,dict_value)

    # square the value in the dict after increase value in the first function.       
    second(list_key,dict_value)

if __name__ == '__main__':
    
    main()

我的预期结果是： 1个 4个 9 16 25 36 49 64 81 100

Answer 1

终于，我找到了我帖子的答案。 但我不喜欢这种方式。因为我们需要在我的子函数中返回更多的值，并添加 For 循环以重新收集数据。 我仍在寻找另一种方法，例如 multiprocessing.Manager() 在程序执行多进程期间保存所有数据。 这是我的 main() 新代码：

def main():
time_start = time.time()
# declare the list and dict
with Manager() as manager :
    # dict_value = manager.dict()
    # list_key = manager.list()
    # list_key = ['A','B','C','D','E','F','G','H','I','K']
    # dict_value = {'A':0,'B':1,'C':2,'D':3,'E':4,'F':5,'G':6,'H':7,'I':8,'K':9}
    list_key = []
    dict_value = {}
    for i in range(1000):
        list_key.append(i)
        dict_value[i]=i
    # multiprocessing for first function.
    with concurrent.futures.ProcessPoolExecutor(max_workers=4) as executor:
        for i in list_key:
            process = executor.submit(first,i,dict_value)
            process_output.append(process)
        
    for result in process_output:
        if result._result[0] in dict_value:
            print(result._result[0])
            print(result._result[1])
            dict_value[result._result[0]]= result._result[1]
        else:
            dict_value.append(result._result)
    print(dict_value)
    print('Finished Increase Value')

# square the value in the dict after increase value in the first function.       
second(list_key,dict_value)
time_end = time.time()
print(time_end-time_start)
print('Finished')