【python3】问题记录

参考：http://www.liujiangblog.com/course/python/76

今天把python2的代码修改兼容python3的几个问题：

• from Queue import Queue修改为from queue import Queue
• import thread修改为import _thread
• print修改
• socket修改：python3发消息需要encode消息buf，接收消息需要decode消息buf:

接收消息：

flag, msg_buf = self.__tcp_client.recv(512)
logger.info("recv msg from mc: %s", msg_buf)
msg_buf = msg_buf.decode()

发送消息：

flag = self.__tcp_client.send(msg.encode())

• opencv库 imshow在线程里调用，会有如下问题：

[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
python: xcb_io.c:165: dequeue_pending_request: Assertion `!xcb_xlib_unknown_req_in_deq' failed.
Aborted (core dumped)

原因是：线程里使用imshow问题
解决方法：
显示代码：

cv2.putText(output_rgb,
                                "FPS: %f" % (fps),
                                (10, 10), cv2.FONT_HERSHEY_SIMPLEX, 0.5,
                                (0, 255, 0), 2)
                    cv2.imshow(video_name, output_rgb)
                    fps_time = time.time()
                    if cv2.waitKey(1) & 0xFF == ord('q'):
                        logger.warn("exit for waitKey!")
                        break

修改为(imshow之前先调下cv2.namedWindow())：

cv2.putText(output_rgb,
                                "FPS: %f" % (fps),
                                (10, 10), cv2.FONT_HERSHEY_SIMPLEX, 0.5,
                                (0, 255, 0), 2)
                    cv2.namedWindow(video_name)
                    cv2.imshow(video_name, output_rgb)
                    fps_time = time.time()
                    if cv2.waitKey(1) & 0xFF == ord('q'):
                        logger.warn("exit for waitKey!")
                        break

• python3的二维列表使用问题