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?

[Spiffy]

"Diez B. Roggisch" <de************ @web.de> wrote in message
news:br******** *****@news.t-online.com...

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

There is no space missing. That is the name of the file on my comp.

[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.

[Diez B. Roggisch]

>> > 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

There is no space missing. That is the name of the file on my comp.

Ok, most probably you'll start to yell at me now, but _there is a space
missing_:

filename = "C:\Python22\Ca nyon.mid"
print "C:\Python22\pl ayb.exe%s"%file name

C:\Python22\pla yb.exeC:\Python 22\Canyon.mid

I have no WinBox here - but I bet even windows likes its commandline
arguments somehow separated from each other. Try executing the line above,
and I bet command.com complains about "Bad command or file name".

Diez

[Fedor]

"Spiffy" <sp****@worldne t.att.net> wrote in message
news:2f******** *************** @bgtnsc04-news.ops.worldn et.att.net...

"Diez B. Roggisch" <de************ @web.de> wrote in message
news:br******** *****@news.t-online.com...

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

There is no space missing. That is the name of the file on my comp.

The ^ points right after exe. (use fixed fonts to see). The command you are
executing is:

C:\Python22\pla yb.exeC:\Python 22\Canyon.mid

There needs to be a space between exe and the second C:

Hope it helps.

[Spiffy]

"Diez B. Roggisch" <de************ @web.de> wrote in message
news:br******** *****@news.t-online.com...

> 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

There is no space missing. That is the name of the file on my comp.

Ok, most probably you'll start to yell at me now, but _there is a space
missing_:

filename = "C:\Python22\Ca nyon.mid"
print "C:\Python22\pl ayb.exe%s"%file name

C:\Python22\pla yb.exeC:\Python 22\Canyon.mid

I have no WinBox here - but I bet even windows likes its commandline
arguments somehow separated from each other. Try executing the line above,
and I bet command.com complains about "Bad command or file name".

Diez

....why would i yell at you? you are trying to help and i appreciate that.
Unfortunately, I have tried various spacings both in the filename and the
os.system call and what happens most often is that a dos box appears and
hangs and python stops responding.

[Spiffy]

"Fedor" <fe***@mailandn ews.com> wrote in message
news:3f******** *************@r eader2.nntp.hcc net.nl...

"Spiffy" <sp****@worldne t.att.net> wrote in message
news:2f******** *************** @bgtnsc04-news.ops.worldn et.att.net...

"Diez B. Roggisch" <de************ @web.de> wrote in message
news:br******** *****@news.t-online.com...

> 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

There is no space missing. That is the name of the file on my comp.

The ^ points right after exe. (use fixed fonts to see). The command you

are executing is:

C:\Python22\pla yb.exeC:\Python 22\Canyon.mid

There needs to be a space between exe and the second C:

Hope it helps.

I have tried your suggestion and put a space after the .exe...the result is
the same as before...a dos box appears and does nothing and python crashes
(stops responding).

[Dennis Lee Bieber]

Spiffy fed this fish to the penguins on Tuesday 09 December 2003 14:06
pm:

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)
If that is the true statement you are using then it is NOT the same as
the command line shown above... THERE'S NO SPACE BETWEEN PROGRAM and
ARGUMENT!

You are trying to run a file named:

C:\Python22\pla yb.exeC:\Python 22\Canyon.mid
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[Fredrik Lundh]

Spiffy wrote:

that indicates that it's supposed to work, don't you think?
IT COULD HAVE BEEN A MISPRINT, DON'T YOU THINK?

sure. if multiple independent sources say the same thing, your
first thought should be that they're all wrong.

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

you mean sys.path?

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

the python path is stored in the sys.path variable. why did you
say python path if you didn't mean it?
I DO NOT THINK THE PROBLEM IS IN HOW I USED THE FUNCTION
NOR WHAT I EXPECTED FROM IT.

no, your problems are obviously elsewhere. good luck with your
programming career.

</F>

[Spiffy]

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

Spiffy wrote:

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

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

sure. if multiple independent sources say the same thing, your
first thought should be that they're all wrong.

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

you mean sys.path?

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

the python path is stored in the sys.path variable. why did you
say python path if you didn't mean it?

I DO NOT THINK THE PROBLEM IS IN HOW I USED THE FUNCTION
NOR WHAT I EXPECTED FROM IT.

no, your problems are obviously elsewhere. good luck with your
programming career.

</F>

It's interesting to me that, although you provided no help or answers to me,
you are convinced that you did. In fact, it is clear from your first
response that your intention has been to amuse yourself by spouting attitude
at me. Hope you had a good time. Meanwhile, Fredo has provided a nice answer
that WORKS... along with an explanation of why my code didn't work. He was
HELPFUL and didn't seem to have the need to belittle me for not being a
professional Python Master. You remind me of one of these teens on IRC who
have no other pleasure in life but to sit around and boot people out of
their precious little chat rooms. I imagine if this was IRC, you would have
booted me at the first post.

[Dennis Lee Bieber]

Dennis Lee Bieber fed this fish to the penguins on Wednesday 10
December 2003 00:31 am:

Talking to myself, again...

Spiffy fed this fish to the penguins on Tuesday 09 December 2003 14:06
pm:

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

What result do you get with just:

os.system("dir" )

-- =============== =============== =============== =============== == <
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/ <