一旦所有值都分配给python，就分配变量并发送到数据库

Question

这是我的第一个python脚本。我试图从Arduino上获取数据，在Raspberry Pi上读取数据并将其保存到数据库中。代码是分开工作的（我可以正确地分配变量并将数据发送到数据库，但似乎不能使它们都工作。我不确定我的逻辑是否有效（将变量设置为null，然后在它们都有值后保存）。谢谢你的意见

    import re
    import serial
    import MySQLdb
    import time

db =MySQLdb.connect(host = "localhost",user = "root",passwd = "example", db = "arduino")
ser =serial.Serial('/dev/ttyACM0',9600) 

humidityPattern = "Humidity\:(\d\d\.\d\d)"
tempDhPattern = "TemperatureDH\:(\d\d\.\d\d)"
barometerPattern = "PressureBMP\:(\d\d\.\d\d)"
tempBmpPattern = "TemperatureBMP\:(\d\d\.\d\d)"
tempTmpPattern = "TemperatureTMP\:(\d\d\.\d\d)"
blLightPattern = "BLLight\:(\d+)"
brLightPattern = "BRLight\:(\d+)"
frLightPattern = "FRLight\:(\d+)"
flLightPattern = "FLLight\:(\d+)"


while 1:
    line = ser.readline()
    humidity = None
    tempDh = None
    pressure = None
    tempBmp = None
    tempTmp = None
    blLight = None
    brLight = None
    frLight = None
    flLight = None

    #Humidity Sensor
    m = re.match(humidityPattern, line)
    if m is not None:      
        humidity = m.group(1)
        print "Humidity is "+humidity

    m = re.match(tempDhPattern, line)
    if m is not None:
        tempDh= m.group(1)
        print "Humidity Temp is "+tempDh

    #Pressure Sensor
    m = re.match(barometerPattern, line)
    if m is not None:
        pressure = m.group(1)
        print "Pressure is "+tempDh

    m = re.match(tempBmpPattern, line)
    if m is not None:
        tempBmp= m.group(1)
        print "Pressure Temp is "+tempBmp

    #Temp Sensor
    m = re.match(tempTmpPattern, line)
    if m is not None:
        tempTmp= m.group(1)
        print "Temp is "+tempTmp

    #Light Sensors
    m = re.match(blLightPattern, line)
    if m is not None:
        blLight= m.group(1)
        print "BL Light is "+ blLight

    m = re.match(brLightPattern, line)
    if m is not None:
        brLight= m.group(1)
        print "BR Light is "+ brLight

    m = re.match(frLightPattern, line)
    if m is not None:
        frLight = m.group(1)
        print "FR Light is "+ frLight

    m = re.match(flLightPattern, line)
    if m is not None:
        flLight = m.group(1)
        print "FL Light is "+ flLight

    if humidity and tempDh and pressure and tempBmp and tempTmp and blLight and brLight and frLight and flLight is not None:
        with db:
            cur = db.cursor()
            cur.execute('insert into weather(humidity, temp_dh, pressure,temp_bmp, temp_tmp, bl_light, br_light, fr_light, fl_light) values("%s", "%s", "%s", "%s", "%s", "%s", "%s", "%s", "%s")'%(humidity, tempDh, pressure, tempBmp, tempTmp, blLight, brLight, frLight, flLight ))
            time.sleep(5)
            print 'upload'

Answer 1

测试中有一个问题：

if humidity and tempDh and pressure and tempBmp and tempTmp and blLight and brLight and frLight and flLight is not None:

它只测试None最后一个变量flLight。但是，如果其他所有字符串都是None或非空字符串，那么这个应该意外地起作用，因为None是虚假的，每个非空字符串都是真实的

所以一个更大的问题是，每次通过循环，你都会扔掉你以前读到的所有值，不管你是否保存了它们

要解决这个问题，请添加一个布尔标志must_init，并在循环的开始处将逻辑更改为：

必须\u init=True 如果为真： line=ser.readline（） 如果必须初始化： 湿度=无 tempDh=无 压力=无 tempBmp=无 MP=无 blLight=无 brLight=无 frLight=无 flLight=无 必须\u init=False

只在with语句的最后一个print 'upload'之后的must_init = True处再次设置must_init = True

这样，您将仅在（A）第一次或（B）将以前的值保存到DB之后立即清空所有变量，这似乎是更正确的逻辑

其他简化的改进是可能的（例如将变量作为dict中的项保留，这样就不必在any检查中枚举它们；在dict中使用与变量dict相同的名称键入重新表达式，以极大地压缩和简化您的代码），但关键点是，添加了must_init布尔标志的代码，正如我之前所建议的，应该可以工作之后您可以改进它！-）