Calling py script from another py prints the value

Question

Hi I am writing python for the first time:

I have a existing getprop.py script that loads the property file and prints the value of a given property:

import sys
import util

if len(sys.argv) < 3:
    print "Error! Usage is: getprop.py [propfile] [propname]"
    sys.exit(1)

props = util.loadprops(sys.argv[1])
if sys.argv[2] in props:
    print props(sys.argv[2]);

Now I need to get the value of a property in another py script, so I modified the above script such that I do not disturb its functionality and I can use it in another script:

import sys
import util

def getpropvalue(propfile, propname):
    props = util.loadprops(propfile)
    if propname in props:
    return props[propname]

if len(sys.argv) < 3:
    print "Error! Usage is: getprop.py [propfile] [propname]"
    sys.exit(1)

else:
    print getpropvalue(sys.argv[1], sys.argv[2]);

and then in other script I import getprop and call the method like getprop.getpropvalue(FILE_NAME, PROP_NAME)and it prints the value of the property on the screen.

why does it prints the value? Is there any better way to solve this problem?

Answer 1

There is a way to run the script only if it was called directly. Add those lines to the end of your getprop code:

if __name__ == "__main__":
    main()

This way the main function is only going to be called if you run the script directly (not importing). Is that what you're looking for?
Some explanation: every running script has a __name__ variable that will be set to "__main__" if you run the script from an IDE or console like python script.py

Answer 2

Change your getprop.py to this:

import sys
import util

def getpropvalue(propfile, propname):
    props = util.loadprops(propfile)
    if propname in props:
    return props[propname]

if __name__ == '__main__':
    if len(sys.argv) < 3:
        print "Error! Usage is: getprop.py [propfile] [propname]"
        sys.exit(1)

    else:
        print getpropvalue(sys.argv[1], sys.argv[2]);

This will prevent the code from being executed when it is imported.