[Tutor] Converting a string to a byte array

[Phil]

On 25/09/17 07:26, Cameron Simpson wrote:
Thank you Cameron and Peter for your replies.

>> I don't understand why this works from the pyqt IDE but not when run 
>> from the console. I suppose the IDE is adding the correct encoding.
> 
> I'm guessing the IDE is python 2 and not doing any encoding at all. In 
> python 2 str _is_ effectively bytes and if you stay in ASCII you just 
> get away with it.
> 

No, the IDE is Eric and as far as I know it's python3 only. Just for 
interest I amended my code to use what you provided and tried it under 
IDLE. There aren't any errors but but my Arduino is not responding. 
However, if I enter python3 mycode.py then it works perfectly. I'm sure 
there's an explanation for this. I have thoney, another python IDE, on a 
raspberrypi I'll try that later and see what the result is. Anyway, it 
works from Eric and from the command prompt.

> So you need to know what your serial device expects. ASCII only?

As it turns out, it doesn't matter if the data is ASCII or UTF-8.

>   mytext = "Fred"
>   mytext = mytext + "\n"
>   mybytes = mytext.encode('utf-8')
>   ser.write(mybytes)
> 
> Notice that I've appended the newline _before_ converting to bytes,

Thank you for the code and the explanation, it's greatly appreciated.

It's all a bit of an anticlimax really. Now that it works I don't know 
what to do with it. Like so many of my projects.

-- 
Regards,
Phil