## 多线程

Python的标准库提供了两个模块：`_thread`和`threading`，`_thread`是低级模块，`threading`是高级模块，对`_thread`进行了封装。绝大多数情况下，我们只需要使用`threading`这个高级模块。

启动一个线程就是把一个函数传入并创建`Thread`实例，然后调用`start()`开始执行。

```python
import time, threading

# 新线程执行的代码
def loop():
    print('thread %s is running...' % threading.current_thread().name)
    n = 0
    while n < 5:
        n = n+1
        print('thread %s >>> %s' % threading.current_thread().name)

print('thread %s is running...' % threading.current_thread().name)
t = threading.Thread(target=loop, name='LoopThread')
t.start()
t.join()
print('Thread %s ended.' % threading.current_thread().name)
```


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