threading僞多線程

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

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

import threading, time
class MyThread(threading.Thread):
    def __init__(self, n):
        super(MyThread, self).__init__()
        self.n = n
    def run(self):
        print("running task", self.n)
        time.sleep(2)
t1 = MyThread("t1")
t2 = MyThread("t2")

t1.run()
t2.run()
t1.start()
t2.start()

import threading, time
def run(n):
    print("task", n)
    time.sleep(2)
    print("task done", n, threading.current_thread())  # 打印子線程

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)  # 把每個線程實例都加進來 不阻塞後面線程的啓動
for t in t_objs:  # 取列表裏的每個線程
    t.join()  # 等待並行的每個線程全都執行完畢 在往下走

print("----all threads has finished...", threading.current_thread(), threading.active_count())  # 打印主線程，程序默認有一個主線程
print("cost:", time.time() - start_time)  # threading.active_count()活躍線程個數  import time,threading

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

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


t1 = MyThread("t1", 2)  # 等待2秒
t2 = MyThread("t2", 4)  # 等待4秒
t1.start()
t2.start()
t1.join()  # wait() 等待t1線程執行完再往下走 程序進程變成串行了 主程序卡主了
t2.join()  # t1執行完之後等t2 等待t2 執行完之後再往下走
print("main threading....")
# 程序末尾有一個默認的join 守護線程

import threading, time
def run(n):
    print("task", n)
    time.sleep(2)
    print("task done", n, threading.current_thread())  # 打印子線程 如果不設置爲守護線程，那麼程序會執行到這裏
start_time = time.time()
t_objs = []
for i in range(50):
    t = threading.Thread(target=run, args=("t %s" % i,))
    t.setDaemon(True)  # 設置爲守護線程 設置爲守護線程之後，主線程執行完之後程序就退出了，不管守護線程有沒有執行完都會退出
    t.start()
    t_objs.append(t)  # 把每個線程實例都加進來 不阻塞後面線程的啓動
# for t in t_objs: #取列表裏的每個線程
#    t.join() #等待並行的每個線程全都執行完畢 在往下走

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