python---Thread

线程简单写法:

import threading,time

def run(n):
    time.sleep(2)
    print("task",n)

#
# t1 = threading.Thread(target=run,args=(10,"t1"))
# t2 = threading.Thread(target=run,args=(3,"t2"))
# t1.start()
# t2.start()

start_time = time.time()
for i in range(50):
    t = threading.Thread(target=run,args=(i,))
    t.start()

exit("exit!")

线程等待：

import threading,time


class MyThread(threading.Thread):
    def __init__(self, n,sleep_time):
        super(MyThread,self).__init__()
        self.n = n
        self.sleeptime = sleep_time

    def run(self):
        print("running task", self.n)
        time.sleep(self.sleeptime)
        print("task done",self.n)


t1 = MyThread("t1",2)
t2 = MyThread("t2",4)

start_time = time.time()
t1.start()
t1.join()
t2.start()
t2.join()
end_time = time.time()
ptime = end_time - start_time
print(ptime)

并发：

def run(n):
    time.sleep(2)
    print("task",n)

start_time = time.time()
t_objs = []
for i in range(50):
    t = threading.Thread(target=run,args=('t-%s'%i,))
    t.start()
    t_objs.append(t)

for t in t_objs:
    t.join()

print("---------------all thread has finished...")
print("cost:",time.time()-start_time)

设置守护进程：

import threading,time

def run(n):
    time.sleep(2)
    print("task done",n,threading.current_thread())

start_time = time.time()
t_objs = []
for i in range(50):
    t = threading.Thread(target=run,args=('t-%s'%i,))
    t.setDaemon(True)  #把当前线程设置成守护线程，需要在start前设置
    t.start()
    t_objs.append(t)

# for t in t_objs:
#     t.join()

print("---------------all thread has finished...",threading.current_thread())
print("cost:",time.time()-start_time)

递归锁：

import threading
import time


def run1():
    print("grad the first part data")
    lock.acquire()
    global num
    num += 1
    lock.release()
    return num


def run2():
    print("grab the second part data")
    lock.acquire()
    global num2
    num2 += 1
    lock.release()
    return num2


def run3():
    lock.acquire()
    res = run1()
    print("-------------between run1 and run2----------")
    res2 = run2()
    lock.release()
    print(res, res2)


num, num2 = 0, 0
lock = threading.RLock()
for i in range(10):
    t = threading.Thread(target=run3)
    t.start()

while threading.active_count() != 1:
    print(threading.active_count())
else:
    print("--------all threads done----------")
    print(num, num2)

信号量：

import threading
import time


def run(n):
    semaphore.acquire()
    time.sleep(1)
    print("run the thread:%s
" % n)
    semaphore.release()


if __name__ == '__main__':

    semaphore = threading.BoundedSemaphore(5)   #设定了最大5个线程同时运行
    for i in range(22):
        t = threading.Thread(target=run, args=(i,))
        t.start()

while threading.active_count() != 1:
    pass
else:
    print("-----------all threads done----------")

event：

import time
import threading

event = threading.Event()



def lighter():
    count = 0
    event.set()
    while True:
        if count > 5 and count <= 10:  #改成红灯
            event.clear()
            print("33[41;1mred light is on ....33[0m")

        elif count > 10:
            event.set() #变绿灯
            count = 0
        else:
            print("33[42;1mgreen light is on....33[0m")
        time.sleep(1)
        count += 1
        print(count)

def car(name):
    while True:
        if event.is_set():
            print("[%s] running..." % name)
        else:
            print("[%s] sees red light , waiting..." % name)
            event.wait()
            print("33[34;1m[%s] green light is on, start going...33[0m" % name)
        time.sleep(1)

light = threading.Thread(target=lighter,)
light.start()

car1 = threading.Thread(target=car, args=("Tesla",))
car1.start()