On Saturday, 4 March 2017 11:29:19 GMT Ralph Corderoy wrote:
> > I then use a bit of string concatenation in a loop to create a string
> > called mp3_files.
>
> But you don't want a string, you want a list, as we both agree. And
> you've got one. :-)
Actually, I've never agreed to anything in that respect :-) However, I did
start off trying to pass the list to the mpg321 command, using a number of
different methods to 'join' it, with no success.
Since then, I've been trying to replicate what happens in the shell and if I
paste a single string containing space-separated filenames after the mpg321, it
works.
Clearly, the subprocess.Popen doesn't work like that, as I'm beginning to
dimly accept.
> > If I put it into my subrocess call as:
> > mp3_player = subprocess.Popen(['mpg321', mp3_files])
> >
> > it raises no complaint, but nothing plays.
>
> I would expect mpg321 to complain on stderr that file `./foo ./bar
> ./xyzzy' can't be found, i.e. there's no directory called `foo .'. But
> you're probably discarding stderr in your tests. (Can't you leave
> stdout and stderr be their default None so mpg321's output goes to the
> same place as your scripts? You're using its -q option to quieten it.)
I'm not. I am only passing the basic mpg321 command to the
subprocess.Popen(), so where should I look for stderr? It's not in the same
directory as my scripts. I thought that by default it went to the console
where the command was issued, which clearly doesn't apply here.
> You need to join your mp3_files list onto the end of your
> fixed-arguments list so Popen() gets the one long list of
> already-separated it needs.
This is the rub. I've tried replicating the working code from the Change
Rings function by saying:
mp3_player = subprocess.Popen(['mpg321', mp3_list])
and I get the error:
TypeError: execv() arg 2 must contain only strings
So what kind of join did you have in mind?
--
Terry Coles
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