How to calculate in Python to compensate for sensor errors?

[Pallantir]

I have a bunch of temperature sensors in the house, and I know that a couple of them are a bit off. One of them, in the aquarium, is one degree off, and I would like that to reflect on the web server page I have made. I tried the way it would be done in LUA, but that's of course not working. Can somebody please tell me how this is done? I'm sure it's dead simple if you know it...

Code: Select all

import time
eg.event.payload_copy = eg.event.payload
my_data = eg.event.payload_copy.split(' ')

td = my_data[2]-1 #temperature and then subtracting one

timeStamp = str(
time.strftime("%Y-%m-%d %H:%M:%S", time.localtime())
)
eg.globals.Akvariet_time = timeStamp
eg.globals.Akvariet_temp = td

That gives me this error:

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11:51:10            Traceback (most recent call last):
11:51:10              Python script "37", line 5, in <module>
11:51:10                td = my_data[2]-1 #temperature and then subtracting one
11:51:10            TypeError: unsupported operand type(s) for -: 'str' and 'int'

I have tried moving the -1 around the script and even doing td2 = td-1, but that doesn't help.

[krambriw]

Code: Select all

td = float(my_data[2])-1.0 #temperature and then subtracting one

[RichPyke]

Change td = my_data[2]-1 to
td = float(my_data[2])-1

It should work then.

From my understanding (basic understanding) td was a string, not a number. You can't -1 from a string. Float changes it to a number... (Please, correct me if I'm wrong)

Edit: ^^ Beat me to it.

[Pallantir]

Synchronized posting should be a part of the olympics, just like syncrhnoized swimming! Thank you very much for the help, both of you! Works like a charm!

[krambriw]

If you rather like to have td as a string with a specified number of decimals, you can do like this:

Code: Select all

td = str( "%.2f" % (float(my_data[2])-1.0))

[Pallantir]

Thanks again! So that's nice to have if I want to calclate a bit more on it, right?