《莫烦python》--Threading学会多线程

• 添加线程 add thread

import threading

# 添加的线程所做的工作
def thread_job():
    print('This is a thread of %s' % threading.current_thread())

def main():
    thread = threading.Thread(target=thread_job,)
    thread.start()

if __name__ == '__main__':
    main()

• join 功能

import threading
import time
def thread_job():
    print('T1 start\n')
    for i in range(10):
        time.sleep(0.1)
    print('T1 finish\n')

def T2_job():
    print('T2 start\n')
    print('T2 finish\n')

def main():
    added_thread = threading.Thread(target=thread_job, name='T1')
    thread2 = threading.Thread(target=T2_job, name='T2')
    added_thread.start()
    thread2.start()
    thread2.join()
    added_thread.join()

    print('all done\n')

if __name__ == '__main__':
    main()

• Queue功能

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()

• 不一定有效率 GIL

import threading
from queue import Queue
import copy
import time

def job(l, q):
    res = sum(l)
    q.put(res)

def multithreading(l):
    q = Queue()
    threads = []
    for i in range(4):
        t = threading.Thread(target=job, args=(copy.copy(l), q), name='T%i' % i)
        t.start()
        threads.append(t)
    [t.join() for t in threads]
    total = 0
    for _ in range(4):
        total += q.get()
    print(total)

def normal(l):
    total = sum(l)
    print(total)

if __name__ == '__main__':
    l = list(range(1000000))
    s_t = time.time()
    normal(l*4)
    print('normal: ',time.time()-s_t)
    s_t = time.time()
    multithreading(l)
    print('multithreading: ', time.time()-s_t)

• lock

import threading

def job1():
    global A, lock
    lock.acquire()
    for i in range(10):
        A += 1
        print('job1', A)
    lock.release()

def job2():
    global A, lock
    lock.acquire()
    for i in range(10):
        A += 10
        print('job2', A)
    lock.release()

if __name__ == '__main__':
    lock = threading.Lock()
    A = 0
    t1 = threading.Thread(target=job1)
    t2 = threading.Thread(target=job2)
    t1.start()
    t2.start()
    t1.join()
    t2.join()

菜鸟教程多线程相关部分：http://www.runoob.com/python3/python3-multithreading.html