如何获取进程的返回值

Question

问题遇到的现象和发生背景

我想使用多进程来处理并行工作，但是不知道如何获取进程的返回值。
我需要保存这些返回值用于后续的处理。

问题相关代码，请勿粘贴截图

from multiprocessing import Process

def run1(N):
    trajlen1 = np.empty(shape=(0, 1))
    etaODAVG1 = np.empty(shape=(0, 1))
    for i in N:
        trajOD, etaODavg = traj_judge(link_start[i], link_start5, link_end[i], link_end5, eta2)
        if len(trajOD) == 1:
            etaODavg1 = simple_eta1[i]
        else:
            etaODavg1 = etaODavg
        etaODAVG1=np.append(etaODAVG1, [[etaODavg1]], axis=0)
        trajlen1=np.append(trajlen1, [[len(trajOD)]], axis=0)
        print('write:', i, 'trajlen:',len(trajOD),'etaODAVG',etaODavg1,'simpale_eta:', simple_eta1[i], 'eta1:', eta1[i])
    return etaODAVG1,trajlen1

def main():
    p1=Process(target=run1,args=(l2[0],))
    p1.start()
    p1.join()
    
if __name__ == '__main__':
    main()

我想要达到的结果

我需要在main（）中获取并保存etaODAVG1,trajlen1这两个返回值。

Answer 1

用进程池吧，还能控制并发量，多香

from concurrent.futures import ProcessPoolExecutor, wait


def run1(num):
    return num, num - 1


def main():
    pool = ProcessPoolExecutor(max_workers=10)
    process = []
    for i in range(10):
        p = pool.submit(run1, i)
        process.append(p)
    wait(process)
    for p in process:
        r1, r2 = p.result()
        print(r1, r2)


if __name__ == '__main__':
    main()