Python：22.多线程

# 多线程
'''
1. _thread：低级模块
2. threading：高级模块，对_thread进行了封装。大多数情况下只需要这个

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
'''
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, n))
        time.sleep(1)
    print('thread %s ended.' % 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)

# Lock
balance = 0
lock = threading.Lock()

def run_thread(n):
    for i in range(100000):
        # 先获取锁
        lock.acquire()
        try:
            # 放心的修改
            pass
        finally:
            # 改完了一定要释放锁
            lock.release()