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我试图让我的树莓派将数据从外部传感器打印到显示器并同时将其保存到 .txt 中。

通过 ssh 在 shell 中启动脚本时，我所做的工作正常。但这会在关闭 shell 后停止脚本。

所以我试图把它放在 rc.local 文件中，以便在启动时启动它。但这只是一半，因为它会在显示屏上显示数据，但不会将其保存到文件中。

import grovepi

from grovepi import *
from grove_rgb_lcd import *
from time import sleep, strftime
from math import isnan


#port definition
dht_sensor_port = 7 
dht_sensor_type = 0 
led_green = 5
led_red = 6
f = open("hwd.txt", "w")

#rgb display color
setRGB(0,255,0)

while True:
    try:
        [ temp,hum ] = dht(dht_sensor_port,dht_sensor_type)
        print("temp =", temp, "C\thumidity =", hum,"%")
        print("{0},{1}\n".format(strftime("%Y-%m-%d %H:%M:%S"),(temp,hum)), file=f)

        if isnan(temp) is True or isnan(hum) is True:
            raise TypeError('nan error')

        t = str(temp)
        h = str(hum)    
        
        setText_norefresh("Temp:" + t + "C\n" + "Humidity :" + h + "%")

        if hum < 40.0 or hum > 60.0:
            grovepi.digitalWrite(led_red,1)
            grovepi.digitalWrite(led_green,0)
        else:
            grovepi.digitalWrite(led_green,1)
            grovepi.digitalWrite(led_red, 0)

    except (IOError, TypeError) as e:
        print(str(e))
        setText("")

    except KeyboardInterrupt as e:
        print(str(e))
        setText("")
        break

    sleep(1)

``
4

1 回答 1

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您正在运行一个无限循环，因此您需要关闭文件流以将更改保存到您的文件中。如果您在没有循环的情况下运行脚本，您可以看到更改已保存，即使没有关闭 Steam，这是因为它隐式处理。因此，您需要打开和关闭文件流，这可以使用with关键字轻松完成。我认为下面的代码适合你。

import grovepi

from grovepi import *
from grove_rgb_lcd import *
from time import sleep, strftime
from math import isnan

# port definition
dht_sensor_port = 7
dht_sensor_type = 0
led_green = 5
led_red = 6

# rgb display color
setRGB(0, 255, 0)

while True:
    try:
        [temp, hum] = dht(dht_sensor_port, dht_sensor_type)
        print("temp =", temp, "C\thumidity =", hum, "%")
        with open("hwd.txt", "w") as f:
            print("{0},{1}\n".format(strftime("%Y-%m-%d %H:%M:%S"), (temp, hum)), file=f)

        if isnan(temp) is True or isnan(hum) is True:
            raise TypeError('nan error')

        t = str(temp)
        h = str(hum)

        setText_norefresh("Temp:" + t + "C\n" + "Humidity :" + h + "%")

        if hum < 40.0 or hum > 60.0:
            grovepi.digitalWrite(led_red, 1)
            grovepi.digitalWrite(led_green, 0)
        else:
            grovepi.digitalWrite(led_green, 1)
            grovepi.digitalWrite(led_red, 0)

    except (IOError, TypeError) as e:
        print(str(e))
        setText("")

    except KeyboardInterrupt as e:
        print(str(e))
        setText("")
        break

    sleep(1)
于 2021-03-22T23:11:29.427 回答