Python在读取行时进入无限循环

Question

I want to read the DS18B20 sensor data with the code below:

filepath = "/sys/bus/w1/devices/w1_bus_master1/w1_master_slaves"

with open(filepath) as fp:
    sensor=fp.readline()
    while sensor:
        print("Sensor: {}".format(sensor.strip()))
        with open("/sys/bus/w1/devices/" + sensor.strip() + "/w1_slave") as fp1:
            sensor_data = fp1.read()
            print(sensor_data.strip())
    sensor=fp.readline()

The problem is that the while loop never steps to the next line, keeps looping at the first one.

What am I missing here?

PS. I'm totaly new with python, this is my very first python code

Answer 1

That because sensor isn't changed within the loop, try this

filepath = "/sys/bus/w1/devices/w1_bus_master1/w1_master_slaves"

with open(filepath) as fp:
    sensor = fp.readline()
        while (sensor):
            print("Sensor: {}".format(sensor.strip()))
            with open("/sys/bus/w1/devices/" + sensor.strip() + "/w1_slave") as fp1:
                sensor_data = fp1.read()
                print(sensor_data.strip())
            sensor=fp.readline()

Answer 2

As discussed in comments, the problem is sensor is never getting updated within loop. It keeps looping through first read value. This can be corrected by indenting the last line of your code.

I suggest using a for loop. When we simply iterate over file handler, we iterate over lines in file.

with open(filepath) as fp:
    for sensor in fp:
        print("Sensor: {}".format(sensor.strip()))
        with open("/sys/bus/w1/devices/" + sensor.strip() + "/w1_slave") as fp1:
            sensor_data = fp1.read()
            print(sensor_data.strip())