Python Raspberry pi - 如果路径不存在，则跳过循环 [英] Python Raspberry pi - If path doesn't exist, skip the loop

问题描述

我有一个函数来收集温度(来自文本文件的值)，它使用部分预定义的路径.但是，如果温度传感器未加载(断开连接)，则有时路径不存在.如果路径不可用，如何设置条件或异常以跳过循环?

I have a function to collect temperature (values from text files) which uses a partly predefined path. However, sometimes the path does not exist if the temperature sensor wasn't loaded (is disconnected). How can I set a condition or exception to skip a loop if a path is not available?

我想使用 continue，但我不知道要设置什么条件.

I wanted to use continue, but i have no idea what condition to set with it.

def read_all(): 

    base_dir = '/sys/bus/w1/devices/'
    sensors=['28-000006dcc43f', '28-000006de2bd7', '28-000006dc7ea9', '28-000006dd9d1f','28-000006de2bd8']

    for sensor in sensors:

        device_folder = glob.glob(base_dir + sensor)[0]
        device_file = device_folder + '/w1_slave'

        def read_temp_raw():
            catdata = subprocess.Popen(['cat',device_file], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
            out,err = catdata.communicate()
            out_decode = out.decode('utf-8')
            lines = out_decode.split('\n')
            return lines

推荐答案

使用 os.path.isfile 和 os.path.isdir() 检查.

for sensor in sensors:
    device_folders = glob.glob(base_dir + sensor)
    if len(device_folders) == 0:
        continue
    device_folder = device_folders[0]
    if not os.path.isdir(base_dir):
        continue
    device_file = device_folder + '/w1_slave'
    if not os.path.isfile(device_file)
        continue
    ....

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