在python中调用超出作用域的线程

Question

我有一个线程，它被定义为在一个程序中连续读取串行数据，并在wxpython中运行UI。

dat = Thread(target=receiving, args=(self.ser,))

它调用的方法"receiving"在一个无限循环中运行

def receiving(ser):
global last_received
buffer = ''
while True:
    date = datetime.date.today().strftime('%d%m%Y')
    filename1 = str(date) + ".csv"
    while date == datetime.date.today().strftime('%d%m%Y'):
        buffer = buffer + ser.read(ser.inWaiting())
        if 'n' in buffer:
            lines = buffer.split('n')
            if lines[-2]:
                last_received = lines[-2]
            buffer = lines[-1]
            print_data =[time.strftime( "%H:%M:%S"), last_received]
            try:
                with open(filename1, 'a') as fob:
                    writ = csv.writer(fob, delimiter = ',')
                    writ.writerow(print_data)
                    fob.flush()
            except ValueError:
                with open('errors.log','a') as log:
                    log.write('CSV file writing failed ' + time.strftime("%H:%M:%S")+' on '+datetime.date.today().strftime('%d/%m/%Y')+'n')
                    log.close()

参数定义为

class SerialData(object):
def __init__(self, init=50):
    try:
        serial_list = serialenum.enumerate()
        self.ser = ser = serial.Serial(
            port=serial_list[0],
            baudrate=9600,
            bytesize=serial.EIGHTBITS,
            parity=serial.PARITY_NONE,
            stopbits=serial.STOPBITS_ONE,
            timeout=None,
            xonxoff=0,
            rtscts=0,
            interCharTimeout=None
        )
    except serial.serialutil.SerialException:
        # no serial connection
        self.ser = None
    else:
        dat = Thread(target=receiving, args=(self.ser,))
        if not dat.is_alive:
            dat.start()
def next(self):
    if not self.ser:
        # return anything so we can test when Serial Device isn't connected
        return 'NoC'
    # return a float value or try a few times until we get one
    for i in range(40):
        raw_line = last_received
        try:
            return float(raw_line.strip())
            time.sleep(0.1)
        except ValueError:
            # print 'Not Connected',raw_line
            time.sleep(0.1)
            return 0

由于Ubuntu 14.04中的一个bug，线程在一段时间后会挂起。我想定期检查线程是否活着，如果不是，就重新启动它。所以我输入了

    def on_timer(self):
    self.text.SetLabel(str(mul_factor*self.datagen.next()))
    if not dat.is_alive():
        dat.start()
    wx.CallLater(1, self.on_timer)

每秒运行一次以更新UI中的数据，但也需要检查线程是否未停止。但这给了我一个错误说"NameError:全局名称'dat'未定义"。我还尝试使用对象名称路径引用线程。但也没起作用。

有人可以帮助我，我如何才能启动线程超出范围?

Answer 1

您似乎想用self.dat替换dat。dat只存在于__init__方法的范围内。我建议阅读Python的作用域规则。