Question

我正在尝试从pir传感器获取信号以将其传输到Web服务。当我运行此代码时

if Current_State==1 and Previous_State==0:
  # PIR is triggered
    output =  subprocess.check_output(["Current_State==1 and enter code herePrevious_State==0","18"]);
     print "  Motion detected!"
     # Tell the Pi to run our speech script and speak the words
     # motion dtected! - anything after the .sh will be read out.
    enter code here` matches = re.search("Current_State==1 and Previous_State==0", output)
     move = int(matches.group(1))
     resultm = client.service.retrieveMove(move)

我收到了这个错误

**Traceback (most recent call last):
  File "pir_5.py", line 48, in <module>
    output =  subprocess.check_output(["Current_State==1 and Previous_State==0", "18"]);
  File "/usr/lib/python2.7/subprocess.py", line 537, in check_output
    process = Popen(stdout=PIPE, *popenargs, **kwargs)
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1259, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory****

Answer 1

根据Python文档中的规范示例，

subprocess.checkoutput()期望运行命令以便它可以捕获输出：

subprocess.check_output(["echo", "Hello World!"])

按预期方式为您提供字符串'Hello World!\n'。

你给出的命令是：

["Current_State==1 and enter code herePrevious_State==0","18"]

这不太可能有效。

你需要实际弄清楚你想做什么（从问题中不清楚）然后根据它构建命令。例如，如果你想以某种方式记录（使用名为logMe的程序），你会这样做：

output = subprocess.check_output(["logMe","CurrState=1 and PrevState=0","18"]);

Answer 2

您需要在列表的第一个参数中为subprocess.check_output提供一个shell命令。然后是第2个，第3个，无论是第一个，第二个，无论shell命令的参数是什么。

Current_State == 1并在此处输入代码Previous_State == 0不是shell命令。

/ bin / true是。

pwd是。

echo foo是。

ls / tmp is。

OSError：[错误2]没有这样的文件或目录

2 个答案: