Question

I have a script a.py :

#!/usr/bin/env python

def foo(arg1, arg2):
    return int(arg1) + int(arg2)

if __name__ == "__main__":
   import sys
   print foo(sys.argv[1], sys.argv[2])`

I now want to make a script that can run the first script and write the output of a.py to a file with some arguments as well. I want to make the automate_output(src,arglist) generate some kind of an output that I can write to the outfile :

import sys

def automate_output(src,  arglist):
    return ""


def print_to_file (src, outfile, arglist):
    print "printing to file %s" %(outfile)
    out = open(outfile, 'w')
    s = open(src, 'r')

    for line in s:
        out.write(line)
    s.close()

    out.write(" \"\"\"\n Run time example: \n") 
    out.write(automate(src, arglist))
    out.write(" \"\"\"\n")
    out.close()


try: 
    src = sys.argv[1]
    outfile = sys.argv[2]
    arglist = sys.argv[3:]
    automate(src, arglist)
    print_to_file(src,outfile,arglist)  
except:
    print "error"
    #print "usage : python automate_runtime.py scriptname outfile args"

I have tried searching around, but so far I do not understand how to pass arguments by using os.system with arguments. I have also tried doing :

import a
a.main()

There I get a NameError: name ‘main’ is not defined

Update :
I researched some more and found subprocess and I’m quite close to cracking it now it seems.
The following code does work, but I would like to pass args instead of manually passing ‘2’ and ‘3’
src = ‘bar.py’
args = (‘2’ , ‘3’)
proc = subprocess.Popen([‘python’, src, ‘2’ , ‘3’], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
print proc.communicate()[0]

Answer 1

This is not a function, it’s an if statement:

if __name__ == "__main__":
    ...

If you want a main function, define one:

import sys

def main():
   print foo(sys.argv[1], sys.argv[2])`

Then just call it if you need to:

if __name__ == "__main__":
    main()