python多线程学习

# 使用函数的方式创建

 import threading

 import time

 def func(arg):

     time.sleep(1)

     print('thread '+str(arg)+" running....")

 if __name__ == '__main__':

     for i in range(10):

         t = threading.Thread(target=func, args=(i,))

         t.start()

# 使用继承 Thread 类的方式创建

import threading

class MyThread(threading.Thread):

    def __init__(self, thread_name):

        # 注意：一定要显式的调用父类的初始化函数。

        super(MyThread, self).__init__(name=thread_name)

    def run(self):

        print("%s正在运行中......" % self.name)

if __name__ == '__main__':

    for i in range(10):

        MyThread("thread-" + str(i)).start() #此行代码也可分开写，先创建 MyThread 对象，在调用 start 方法

"""Start the thread's activity.

    It must be called at most once per thread object. It arranges for the

    object's run() method to be invoked in a separate thread of control.

    This method will raise a RuntimeError if called more than once on the

    same thread object.

"""

"""Wait until the thread terminates.

    This blocks the calling thread until the thread whose join() method is

    called terminates -- either normally or through an unhandled exception

    or until the optional timeout occurs.

    When the timeout argument is present and not None, it should be a

    floating point number specifying a timeout for the operation in seconds

    (or fractions thereof). As join() always returns None, you must call

    is_alive() after join() to decide whether a timeout happened -- if the

    thread is still alive, the join() call timed out.

    When the timeout argument is not present or None, the operation will

    block until the thread terminates.

    A thread can be join()ed many times.

    join() raises a RuntimeError if an attempt is made to join the current

    thread as that would cause a deadlock. It is also an error to join() a

    thread before it has been started and attempts to do so raises the same

    exception.

    """

import threading

import time

def func(arg):

    time.sleep(1)

    print('thread '+str(arg)+" running....")

if __name__ == '__main__':

    start = time.time()

    threads = []

    for i in range(10):

        t = threading.Thread(target=func, args=(i,))

        threads.append(t)

    for t in threads:

        t.start()

    for t in threads:

        t.join()

    print(time.time() - start)

import threading

import time

def func_fs(name):

    with open(f"{name}.txt", "w") as target:

        time.sleep(5) # 假装写入很久

        target.write("这是一段很长的文本")

if __name__ == "__main__":

    start = time.time()

    l_thread = []

    for i in range(2):

        t = threading.Thread(target=func_fs, args=(i,))

        l_thread.append(t)

    for t in l_thread:

        t.start()

    for t in l_thread:

        t.join()

    print(time.time() - start)