每天进步一点点-多进程和多线程以及内置队列使用

多进程

import multiprocessing as mp
import threading as td
import time


def job(q):
    res = 0
    for i in range(10000000):
        res += i + i ** 2 + i ** 3
    q.put(res)  # queue


def multicore():
    q = mp.Queue()
    p1 = mp.Process(target=job, args=(q,))
    p2 = mp.Process(target=job, args=(q,))
    p1.start()
    p2.start()
    p1.join()
    p2.join()
    res1 = q.get()
    res2 = q.get()
    print('multicore:', res1 + res2)


def normal():
    res = 0
    for _ in range(2):  # 线程或进程都构造了两个，进行了两次运算，所以这里循环两次
        for i in range(10000000):
            res += i + i ** 2 + i ** 3
    print('normal:', res)


def multithread():
    q = mp.Queue()
    t1 = td.Thread(target=job, args=(q,))
    t2 = td.Thread(target=job, args=(q,))
    t1.start()
    t2.start()
    t1.join()
    t2.join()
    res1 = q.get()
    res2 = q.get()
    print('multithread:', res1 + res2)


if __name__ == '__main__':
    st = time.time()
    normal()
    st1 = time.time()
    print('normal time:', st1 - st)
    multithread()
    st2 = time.time()
    print('multithread time:', st2 - st1)
    multicore()
    print('multicore time:', time.time() - st2)

''' 运算结果如下
normal: 4999999666666716666660000000
normal time: 20.65348792076111
multithread: 4999999666666716666660000000
multithread time: 20.157374143600464
multicore: 4999999666666716666660000000
multicore time: 13.649165630340576
'''

内置queue

# 因为 线程函数没有返回值,计算的结果无法返回,所以需要一个队列将这个值存放起来,以便后续使用

import threading
import time
from queue import Queue
 
def job(l,q):
    for i in range(len(l)):
        l[i] = l[i]**2
    q.put(l)
 
def multithreading():
    q = Queue()
    threads = []
    data = [[1,2,3],[3,4,5],[4,4,4],[5,5,5]]
    for i in range(4):
        t = threading.Thread(target=job, args=(data[i], q))
        t.start()
        threads.append(t)
    for thread in threads:
        thread.join()
    results = []
    for _ in range(4):
          results.append(q.get())
    print(results)
 
if __name__ == '__main__':
    multithreading()
# [[1, 4, 9], [9, 16, 25], [16, 16, 16], [25, 25, 25]]