这TM关GIL毛事 简直躺枪
要记住 断然给你提GIL的 要么是高手 要么是SB 有GIL还有multiprocessing呢 多线程最需要注意的应该是线程安全
这是threading.join的文档
join([timeout])
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 isAlive() 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.

看了之后你就发现 在上面加上t.join就和下面遍历的写法实质上是一模一样的.
一般网上很多教程给你加上setDaemon 加上join 你可以试着不加看是什么样的。等你熟悉了之后你就晓得那时候该用这些 哪时候不该用