线程之间的执行顺序是无序的

import threading
import time
def rask():
    time.sleep(1)
    print(threading.current_thread())
    pass
if __name__ == '__main__':
    for item in range(5):
        rask_threading = threading.Thread(target=rask)
        rask_threading.start()
        pass

• 执行结果

<Thread(Thread-2, started 18756)>
<Thread(Thread-1, started 20816)>
<Thread(Thread-4, started 18496)>
<Thread(Thread-3, started 7556)>
<Thread(Thread-5, started 20920)>

主线程会等待子线程执行完结果

• 如果子线程是一个死循环的话？
• 让子线程守护主线程demaon（就可以结束死循环）

import threading
import time
def rask():
    while True:
        print("正在执行中.....")
        time.sleep(0.2)
        pass
    pass
if __name__ == '__main__':
    # 方法一：
    # rask_threading = threading.Thread(target=rask, daemon=True)
    rask_threading = threading.Thread(target=rask)
    # 方法二
    rask_threading.setDaemon(True)
    rask_threading.start()
    time.sleep(1)
    print("over")