如何从线程完成时获取结果？

Question

下面的代码启动线程数和打印他们都做了之后的结果：

import threading 

results = [None] * 5 
threads = [None] * 5 

def worker(i): 
    results[i] = i 

for i in range(5): 
    threads[i] = threading.Thread(target=worker, args=(i,)) 
    threads[i].start() 

# here I would like to use the results of the threads which are finished 
# while others still run 

for i in range(5): 
    threads[i].join() 

# here I have the results but only when all threads are done 
print(results) 

正如在代码中提到，我想用这些而另一些则仍在运行完线程的结果。 这样做的正确方法是什么？

我应该只是开始这将有while True:环和一个新的条目results连续检查或者是有这样操作的BUIL的机制（如threading.Thread调用，它会指向一个部分一个新的线程线程完成时的回调）？

Answer 1

由于您使用的Python 3，concurrent.futures是一个比threading更适合：

从multiprocessing.pool

import concurrent.futures 

results = [None] * 5 

def worker(i): 
    results[i] = i 

with concurrent.futures.ThreadPoolExecutor(5) as pool: 
    futmap = {pool.submit(worker, i): i for i in range(len(results))} 
    for fut in concurrent.futures.as_completed(futmap): 
     print("doing more stuff with", futmap[fut])