running non-python progs from python

[Spiffy]

hello, i'm fairly new to python programming and programming in general, but
i have written a python prog that creates a MIDI file (.mid) and I want to
be able to play it from another prog which is written in BASIC.
It's a command-line prog that takes the MIDI filename as a parameter and
plays the file.
The 'Learning Python' book talks about using the os.system call, but I
haven't been able to get this to work.
How can I run this other program from a python script and pass the filename
as a parameter?

[Michel Claveau/Hamster]

Hi !

You can also do (sample) :

import os
vret = os.popen('c:\\p files\\lplayer. exe')
print vret

@+
--
Michel Claveau

[Fredrik Lundh]

"Spiffy" wrote:

The 'Learning Python' book talks about using the os.system call, but I
haven't been able to get this to work.
"it doesn't work" is a really lousy way to describe a problem what did you
do, what happened, and what did you expect would happen instead?

also see:

http://www.catb.org/~esr/faqs/smart-...ons.html#intro
How can I run this other program from a python script and pass the filename
as a parameter?

import os

filename = "myfile"
os.system("prog ram %s" % filename)

</F>

[Spiffy]

"Michel Claveau/Hamster" <No********@No. Spam.mclaveau.N o.Spam.com> wrote in
message news:br******** **@news-reader2.wanadoo .fr...

Hi !

You can also do (sample) :

import os
vret = os.popen('c:\\p files\\lplayer. exe')
print vret

@+
--
Michel Claveau
Hello Michel, thanks for taking the time to respond. Unfortunately, when I
tried to run your sample code (changing the name of the file, of course), it
did nothing.

How can I run this other program from a python script and pass the filename as a parameter?
import os

filename = "myfile"
os.system("prog ram %s" % filename)

</F>

Fredrik, the example you provided is virtually the same as the one from the
"Learning Python" book. When I run it, the dos command line appears with the
message 'Bad command or file name". Both the .exe and the .mid file are in
the python path and the spelling has been checked.
What I expected to happen was that the os.system call would start the .exe
and begin playing the .mid file. This does not happen. This is what I meant
when I said I haven't been able to get this to work.
"it doesn't work" is a really lousy way to describe a >problem what did youdo, what happened, and what did you expect would >happen instead?

also see:

http://www.catb.org/~esr/faqs/smartquestions.html#intro

Pardon me for being a newbie, but if you don't have an answer, why do you
have to give me attitude?

[Fredrik Lundh]

"Spiffy" wrote:

How can I run this other program from a python script and pass the filename

as a parameter?

import os

filename = "myfile"
os.system("prog ram %s" % filename)

</F>

Fredrik, the example you provided is virtually the same as the one from the
"Learning Python" book.

that indicates that it's supposed to work, don't you think?
When I run it, the dos command line appears with the message 'Bad command
or file name".
that indicates that Windows cannot find the command, don't you think?
Both the .exe and the .mid file are in the python path and the spelling has
been checked.
you mean sys.path? that's the problem, most likely. As mentioned in the
documentation, os.system() executes the command just as if you've typed
it in a "DOS box". Windows doesn't look at the Python path when you do
that, so to make sure Windows finds the command, you have to add it to
the Windows path (the PATH environment variable), or provide the full path
to os.system().

program = r"x:\full\path\ to\program"
filename = "..."
os.system("%s %s" % (program, filename))

the os.path.abspath () function can be useful in cases like this; it makes sure
that if your program can find a file, another program can also find it:

program = os.path.abspath ("x:/somewhere/program")
filename = os.path.abspath ("somefile")
os.system("%s %s" % (program, filename))

(if the filename may contain spaces, you may have to add quotes around
the second %s)

the relevant manual page contains more information on os.system, and
mentions a couple of alternatives (os.startfile, os.spawnlp, etc):

§http://www.python.org/doc/current/lib/os-process.html
Pardon me for being a newbie, but if you don't have an answer, why do you
have to give me attitude?

os.system() is still the answer; the problem is in how you used it and what
you expected from it, not in the function itself. You cannot expect people
to read your mind, and then complain when they fail.

</F>

[Dennis Lee Bieber]

Spiffy fed this fish to the penguins on Tuesday 09 December 2003 00:38
am:

from the "Learning Python" book. When I run it, the dos command line
appears with the message 'Bad command or file name". Both the .exe and
the .mid file are in the python path and the spelling has been
checked. What I expected to happen was that the os.system call would
start the .exe and begin playing the .mid file. This does not happen.
This is what I meant when I said I haven't been able to get this to
work.
So include (don't retype or paraphrase, use cut&paste) the /exact/
code which is failing, AND the exact command window output...

Among other things, I don't think os.system() uses the /Python/ path
-- its the equivalent of opening a new command prompt and typing the
command; so it is the OS search path that is used.

Open a command window, and type the exact command you think you are
using in os.system()

-- =============== =============== =============== =============== == <
wl*****@ix.netc om.com | Wulfraed Dennis Lee Bieber KD6MOG <
wu******@dm.net | Bestiaria Support Staff <
=============== =============== =============== =============== == <
Bestiaria Home Page: http://www.beastie.dm.net/ <
Home Page: http://www.dm.net/~wulfraed/ <

[Spiffy]

"Fredrik Lundh" <fr*****@python ware.com> wrote in message
news:ma******** *************** *************** @python.org...

"Spiffy" wrote:

How can I run this other program from a python script and pass the filename

as a parameter?

import os

filename = "myfile"
os.system("prog ram %s" % filename)

</F>

Fredrik, the example you provided is virtually the same as the one from the "Learning Python" book.

that indicates that it's supposed to work, don't you think?

IT COULD HAVE BEEN A MISPRINT, DON'T YOU THINK?

When I run it, the dos command line appears with the message 'Bad command or file name".

that indicates that Windows cannot find the command, don't you think?

Both the .exe and the .mid file are in the python path and the spelling has been checked.

you mean sys.path?

IF I HAD MEANT sys.path, I WOULD HAVE SAID sys.path, DON'T YOU THINK?

that's the problem, most likely. As mentioned in the documentation, os.system() executes the command just as if you've typed
it in a "DOS box". Windows doesn't look at the Python path when you do
that, so to make sure Windows finds the command, you have to add it to
the Windows path (the PATH environment variable), or provide the full path
to os.system().

program = r"x:\full\path\ to\program"
filename = "..."
os.system("%s %s" % (program, filename))

the os.path.abspath () function can be useful in cases like this; it makes sure that if your program can find a file, another program can also find it:

program = os.path.abspath ("x:/somewhere/program")
filename = os.path.abspath ("somefile")
os.system("%s %s" % (program, filename))

(if the filename may contain spaces, you may have to add quotes around
the second %s)
TYPING THE FULL PATH GIVES ME THE SAME RESULT: NOTHING. THE ABOVE CODE USING
os.path.abspath CAUSES A DOS BOX TO APPEAR AND DO NOTHING WHILE PYTHON
CRASHES. the relevant manual page contains more information on os.system, and
mentions a couple of alternatives (os.startfile, os.spawnlp, etc):

§http://www.python.org/doc/current/lib/os-process.html

Pardon me for being a newbie, but if you don't have an answer, why do you have to give me attitude?
os.system() is still the answer; the problem is in how you used it and

what you expected from it, not in the function itself. You cannot expect people to read your mind, and then complain when they fail.
I DID NOT ASK ANYONE TO READ MY MIND, NOR DID I COMPLAIN THAT ANYONE COULD
NOT READ MY MIND.
I DO NOT THINK THE PROBLEM IS IN HOW I USED THE FUNCTION NOR WHAT I EXPECTED
FROM IT.

[Michel Claveau/Hamster]

Du calme, s'il vous plaît...

--
Michel Claveau

[Spiffy]

"Dennis Lee Bieber" <wl*****@ix.net com.com> wrote in message
news:ef******** ****@beastie.ix .netcom.com...

Spiffy fed this fish to the penguins on Tuesday 09 December 2003 00:38
am:

from the "Learning Python" book. When I run it, the dos command line
appears with the message 'Bad command or file name". Both the .exe and
the .mid file are in the python path and the spelling has been
checked. What I expected to happen was that the os.system call would
start the .exe and begin playing the .mid file. This does not happen.
This is what I meant when I said I haven't been able to get this to
work.
So include (don't retype or paraphrase, use cut&paste) the /exact/
code which is failing, AND the exact command window output...

Among other things, I don't think os.system() uses the /Python/

path -- its the equivalent of opening a new command prompt and typing the
command; so it is the OS search path that is used.

Open a command window, and type the exact command you think you are using in os.system()

--

> In the command window the call to the program with the name of the .mid
file to be played works just fine. Here is what it looks like....exactly :
C:\Python22>pla yb Canyon.mid

Here is the code used to call it from Python:
import os
filename = "C:\Python22\Ca nyon.mid"
os.system("C:\P ython22\playb.e xe%s"%filename)
....this causes a dos box to appear which promptly hangs and does nothing, at
which time Python stops responding. Vartiations on this will cause the dos
box to appear with the message "Bad command or file name".
=============== =============== =============== =============== == < > wl*****@ix.netc om.com | Wulfraed Dennis Lee Bieber KD6MOG <
> wu******@dm.net | Bestiaria Support Staff <
> =============== =============== =============== =============== == <
> Bestiaria Home Page: http://www.beastie.dm.net/ <
> Home Page: http://www.dm.net/~wulfraed/ <

[Diez B. Roggisch]

> Here is the code used to call it from Python:

import os
filename = "C:\Python22\Ca nyon.mid"
os.system("C:\P ython22\playb.e xe%s"%filename)
...this causes a dos box to appear which promptly hangs and does nothing,
at which time Python stops responding. Vartiations on this will cause the
dos box to appear with the message "Bad command or file name".

Looks like there is a space missing -

os.system("C:\P ython22\playb.e xe %s"%filename)
^

Diez