Calling a Python Script From Another Python Script

Question

I'm experimenting with something new to me; calling one python script from another. The end objective is to have several small 'calling scripts' make a call to the same single big script passing it variables, rather than maintaining several individual 'big scripts'. I'm running into a snag with the 'big script when I have def main(): in it. Basic premise: """ script_ 1 playing the role of little calling script """ var1 = 'A' var2 = 'B' var3 = 'C' import Script_2 ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ """ script_2 playing the role of the single big script """ from __main__ import * print(var1) print(var2) print(var3) ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ This initial approach works just fine: all the variables get passed and then printed But if I change script_2 to wrapping it in a def main(): nothing happens. No errors, but more importantly, no prints: from __main__ import * def main(): print(var1) print(var2) print(var3) if __name__== "__main__": main()‍‍‍‍‍‍‍‍‍ It's as if the lines 8 & 9 are overruled by line 1? Is there a way to use a def main(): wrapper in a script being called by another?

DanPatterson_Retired · Answer

# -*- coding: utf-8 -*- """ main_script.py ======= documentation """ import sys from helper import func1, func2, func3 val1 = func1() val2 = func2() val3 = func3(5) print("magic {} happens {} on Fridays {}".format(val1, val2, val3)) # =========================================================================== # if __name__ == "__main__": """optional location for parameters""" print(sys.argv[0])‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ now the helper # -*- coding: utf-8 -*- """ helper.py ======= """ import sys def func1(): """Do amazing things""" return 5 def func2(): """Do more amazing things""" return 2 def func3(val): """Do amazing things""" return val + 5 # ==== Processing finished ==== # =========================================================================== # if __name__ == "__main__": """optional location for parameters""" print(sys.argv[0])‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ put both in the same folder run main_script compare to running just helper.py

DanPatterson_Retired · Answer

Joe, the example I give is for when you have functionality that you want to use often and not repeat it.  You put it into a separate script and import the functions from the script as you need them.  In fact your main script need not contain any 'def' s at all, you simply import them from other scripts, use them in calculations and so on. When you run a script, it's name is __main__.  If you want to do something when you run a script you can put it below that line,  it need not be a function called main()

JoeBorgione · Answer

I think the fog is lifting for me with respect to __name__ as I've been able to come up with a solution to this that I like. Consequently when calling a script from another I have two options: Option 1 is to not use: if __name__== "__main__": main()‍‍ at the end of the script. But if I really want to use it, I make a slight adjustment to Script_2.py: """ script_2 playing the role of the single big script """ from __main__ import * def main() print(var1) print(var2) print(var3) if __name__ = 'Script_2': main()‍‍‍‍‍‍‍‍‍‍‍‍‍‍ Line 13 is the crucible. As I understand it, when a script is executed as itself, __name__ = '__main_'‍ But since I'm calling Script_2.py from another script, that goes out the window because now: __name__ = 'Script_2'‍ Remember, print() is always your friend: I put one in both Script_1 ad Script_2 in the appropriate places and things came together.....