Python索引错误索引列表超出范围

Question

我有一个python代码，可将串行命令发送到设备并从中获取答复。

 def control(command):
     serialport= serial.Serial ("/dev/ttyAMA0", 9600, timeout=0.5)
     serialport.write(command)
     return serialport.readlines(1)

我有一本字典，它映射一些代码以传递给command 。 然后我将打印出答复。

response = control(code_map.get(key,None))
print response, type(response)

编辑：打印输出的示例是['\\x03O?0201\\r'] <type 'list'>

得到答复后，我必须检查答复中的某些字符，例如：

if "O?" in response[0]:
    if "01" in response[0]:
        if "0100" in response[0]:
            status="off"
        else:
            status="on"
    else:
        status="off"

如果只回复一次，则效果很好。 但是，当有2个或更多请求时，它将引发该索引错误，并且不会显示状态。

这是我的JavaScript，可发布并获取状态回复：

        $('#monitor').click(function(){
            setInterval(function(){
                    $('#status_table tr [id^="monitor_"]:checked').each(function () {
                        monitoring($(this).parents('tr'));
                     });
                },15000);
        });

        function monitoring($row) {
            $('#test').append("checked");
            fbType = $row.find('td:nth-child(3)').html();
            fbNum = $row.find('td:nth-child(4)').html();
            eachStatus =$row.find('td:nth-child(5)').attr('id');
            $('#test').append(fbType + ' '+ fbNum+' '+ eachStatus +'<br>');

            $.post('/request', {inputText: fbNum,key_pressed: fbType.toString()}).done(function (reply) {
                if (reply == "on") {
                    $('#status_table tr #status_'+eachStatus).append("on");
                    $('#test').append("on");
                } else if (reply =="off") {
                    $('#status_table tr #'+eachStatus).empty().append("off");
                    $('#test').append("off");
                }
            });
        }

追溯：

[03/May/2013:14:36:35] HTTP Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/CherryPy-3.2.2-py2.7.egg/cherrypy/_cprequest.py", line 656, in respond
    response.body = self.handler()
  File "/usr/local/lib/python2.7/dist-packages/CherryPy-3.2.2-py2.7.egg/cherrypy/lib/encoding.py", line 188, in __call__
    self.body = self.oldhandler(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/CherryPy-3.2.2-py2.7.egg/cherrypy/_cpdispatch.py", line 34, in __call__
    return self.callable(*self.args, **self.kwargs)
  File "remote_control_keypad_new52.py", line 677, in request
    if "O?" in response[0]:
IndexError: list index out of range

[03/May/2013:14:36:35] HTTP
Request Headers:
  Content-Length: 31
  REFERER: http://localhost:8080/
  HOST: localhost:8080
  ORIGIN: http://localhost:8080
  CONNECTION: Keep-Alive
  Remote-Addr: 127.0.0.1
  ACCEPT: */*
  USER-AGENT: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-us) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.22+ Midori/0.4
  X-REQUESTED-WITH: XMLHttpRequest
  ACCEPT-LANGUAGE: en-us;q=0.750
  Content-Type: application/x-www-form-urlencoded; charset=UTF-8
  ACCEPT-ENCODING: gzip, deflate
127.0.0.1 - - [03/May/2013:14:36:35] "POST /request HTTP/1.1" 500 1460 "http://localhost:8080/" "Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-us) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.22+ Midori/0.4"
['\x03O?0101\r\x03O?0201\r'] <type 'list'>
on
127.0.0.1 - - [03/May/2013:14:36:36] "POST /request HTTP/1.1" 200 2 "http://localhost:8080/" "Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-us) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.22+ Midori/0.4"
Button one is assigned with Response number None
Button one is assigned with Response number None
Button one is assigned with Response number None
output number selected is 01
R!None
R!None
R!None
R!None
Button one is assigned with Response number None
Button one is assigned with Response number None
Button one is assigned with Response number None
output number selected is 02
R!None
R!None
R!None
R!None
[03/May/2013:14:36:50] HTTP Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/CherryPy-3.2.2-py2.7.egg/cherrypy/_cprequest.py", line 656, in respond
    response.body = self.handler()
  File "/usr/local/lib/python2.7/dist-packages/CherryPy-3.2.2-py2.7.egg/cherrypy/lib/encoding.py", line 188, in __call__
    self.body = self.oldhandler(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/CherryPy-3.2.2-py2.7.egg/cherrypy/_cpdispatch.py", line 34, in __call__
    return self.callable(*self.args, **self.kwargs)
  File "remote_control_keypad_new52.py", line 674, in request
    response = comfort_control(code_map.get(key,None))
  File "remote_control_keypad_new52.py", line 639, in comfort_control
    return serialport.readlines(1)
  File "/usr/lib/python2.7/dist-packages/serial/serialposix.py", line 456, in read
    raise SerialException('device reports readiness to read but returned no data (device disconnected?)')
SerialException: device reports readiness to read but returned no data (device disconnected?)

[03/May/2013:14:36:50] HTTP
Request Headers:
  Content-Length: 31
  REFERER: http://localhost:8080/
  HOST: localhost:8080
  ORIGIN: http://localhost:8080
  CONNECTION: Keep-Alive
  Remote-Addr: 127.0.0.1
  ACCEPT: */*
  USER-AGENT: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-us) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.22+ Midori/0.4
  X-REQUESTED-WITH: XMLHttpRequest
  ACCEPT-LANGUAGE: en-us;q=0.750
  Content-Type: application/x-www-form-urlencoded; charset=UTF-8
  ACCEPT-ENCODING: gzip, deflate
127.0.0.1 - - [03/May/2013:14:36:50] "POST /request HTTP/1.1" 500 1839 "http://localhost:8080/" "Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-us) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.22+ Midori/0.4"
['\x03O?0101\r\x03O?0201\r'] <type 'list'>
on
127.0.0.1 - - [03/May/2013:14:36:51] "POST /request HTTP/1.1" 200 2 "http://localhost:8080/" "Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-us) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.22+ Midori/0.4"
^C[03/May/2013:14:36:56] ENGINE Keyboard Interrupt: shutting down bus
[03/May/2013:14:36:56] ENGINE Bus STOPPING

Answer 1

也许您的回应是空的清单

>>> response = []
>>> response[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: list index out of range

也许您的设备并不总是足够快以响应此问题

serialport.write(command)
return serialport.readlines(1)

特别是如果有两个重叠的请求，则需要确保程序一次将它们提供给设备一次。