Call external program from python and get its output

Question

I want to call a program (.exe), which is written in C++ and compiled, from Python. The executable takes as input two files and returns a score.

I need to do this for multiple files. So, I would like to write a small script in python which loops over multiple files, passes them to the executable and gets back the values.

Now, I have done my search and I know about SWIG and Boost::Python may be an option but I was trying to find if there is an easier way. I do not need to 'extend' the C++ program. I simply want to call it just like I would from a command line and get the returned number.

@TorelTwiddler that's not what he wants to do -- that answer just returns the return code, not the output of the program. — agf
– agf, Commented Sep 30, 2011 at 0:02
The correct duplicate is What's a good equivalent to python's subprocess.check_call that returns the contents of stdout? — agf
– agf, Commented Sep 30, 2011 at 0:03

agf · Accepted Answer · 2011-09-30 00:00:58Z

5

To run an external program and get its output, use subprocess.check_output on Python 2.7+. The example from the docs:

>>> subprocess.check_output(["ls", "-l", "/dev/null"])
'crw-rw-rw- 1 root root 1, 3 Oct 18  2007 /dev/null\n'

check_call just returns the return code of the program, not the output.

answered Sep 30, 2011 at 0:00

agf

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icktoofay · Accepted Answer · 2011-09-30 00:02:52Z

2

You can use the subprocess module for that.

result = subprocess.check_output(['your_program.exe', 'arg1', 'arg2'])

edited Sep 30, 2011 at 0:02

answered Sep 29, 2011 at 23:55

icktoofay

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