AttributeError：'NoneType'对象没有属性'group'

Question

please help as i am trying to use a raspberry pi pir sensor to transfer the data collected by the pir sensor(which is 1 or 0 ) to the web service and i got this error

Traceback (most recent call last):
  File "pir_5.py", line 54, in <module>
    moveHold = float(matches.group(1))
AttributeError: 'NoneType' object has no attribute 'group'

and this is my code

while True :

    # Read PIR state
    Current_State = GPIO.input(GPIO_PIR)

    if Current_State==1 and Previous_State==0:
      # PIR is triggered
      output =  subprocess.check_output(["echo", "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.
      matches = re.search("Current_State==1 and Previous_State==0", output)
      moveHold = float(matches.group(1))
      resultm = client.service.retrieveMove(moveHold)

      cmd_string = './speech.sh motion detected!'
      # now run the command on the Pi.
      os.system(cmd_string)
      # Record previous state
      Previous_State=1
    elif Current_State==0 and Previous_State==1:
      # PIR has returned to ready state
      print "  Ready"
      Previous_State=0

    # Wait for 10 milliseconds
    time.sleep(0.01)

Answer 1

Then obviously the output does not contain the expected string. (How should it, when it is generated by calling echo 18 ?) Thus,

  matches = re.search("Current_State==1 and Previous_State==0", output)

returns None , which has no .group() for

  moveHold = float(matches.group(1))

so that you get the said exception.

You should change that to

    matches = re.search("Current_State==1 and Previous_State==0", output)
    if matches:
        moveHold = float(matches.group(1))
        resultm = client.service.retrieveMove(moveHold)
        ...
    else:
        # code for if it didn't match

Answer 2

At the point where you wrote

matches.group(...)

matches was None . It seems that your regex search failed to find a match. If it is possible for the regex search to fail, then you need to handle that scenario explicitly:

if matches is None:
    ....

Or perhaps the real problem is that your code to perform the search is just wrong.

Rather than me trying to tell you precisely what to do to fix the problem, the main point for you to learn is how to interpret this particular error message.