Run python function in command line

Question

I'm beginner in Python and I have problem to run my function in command line, through IDLE it's working, but I need to run it in command line, because I will have to make from it executable file...

So my problem... I have this

file name test.py

class A
def myFunction(a,b)
print a,b

myFunction calls Class, from IDLE it's enough to write myfunction(a,b), but from command line I don't know what to do

My goal is

to run function from command line with command: name_of_the_file arg1 arg2 --> test a b

I looked I think everywhere and tried everything, most common what I found was to add to my function this command

if __name__ == '__main__':
 a = sys.argv[0]
 b = sys.argv[1]
 myFunction(a,b)

So it was

class A:
 some process which calls myFunction
def myFunction(a,b)
 print a,b
if __name__ == '__main__':
 a = sys.argv[0]
 b = sys.argv[1]
 myFunction(a,b)

and then I called it from command line with test a b, but I got only errors

I use Python 2.7

Thank you for your help

• Ignacio Vazquez-Abrams: docs.python.org/2/tutorial/index.html
• Jason Sperske: If you put a function inside a class then you need an instance of that class to call that function (if I understand your question correctly)
• Vorsprung: your stuff doesn't compile because there are missing colons and whitespace. What is your question exactly?

Answer 1

Some issues with your code:

1. Python is case-sensitive. The keyword is class, not Class.
2. After the line class A there has to be a colon: class A:

3. If the function myFunction is supposed to be part of class A, it has to be indented:

   class A:
    def myFunction(a,b)
   

4. Methods of classes should have self as first parameter: def myFunction(self, a, b)

5. After def myFunction(self, a,b) there has to be a colon: def myFunction(self, a,b):

6. Your function must have at least one line of indented code following. If it is supposed to do nothing, you can use the keyword `pass:

   def myFunction(self, a,b):
    pass
   

7. If you want to use sys.argv you first have to import sys at the beginning of your code with import sys.

8. myFunction is part of a class, you first have to instantiate it to use the function:

   Av = A()
   Av.myFunction(a,b)
   

9. The first commandline argument is the second entry of sys.argv, not the first.

However it seems to me that you don't want a class anyway, so just write:

def myFunction(a,b):
 pass
if __name__ == '__main__':
 a = sys.argv[1]
 b = sys.argv[2]
 myFunction(a,b)

Also you call python scripts with python file.py arg1 arg2. If you want to omit python at the beginning then you can (in unix-like systems) add a shebang in the first line of the python-file: #!/usr/bin/env python. Then as long as the execution flag is set chmod +x file.py it may be called like ./file.py arg1 arg2.

• Kuba: Sorry, my question wasn't clear, I edited it! I compiled program and run it in cmd by test 1 2 I used a = sys.argv[1] b = sys.argv[2] I get error IndexError: list index out of range Now I would like to just print a and b and after work with them
• user3072164: @user3149628 Your code still contains some of the errors mentioned. Also it is less clear to me now what you want. Please write down exactly what you typed where and what output you got.
• Kuba: ok, your advice helped me, i set argv to 1 and 2 and now it's working (i had to fix input at if name == 'main': - before i tested it in myFunction() ) now if I run from command line python test.py 3 2 it works, but after compilation to exe it don't work, do I have mistake in the code, or compilation isn't good?
• Kuba: :) I reinstall py2exe and now it's working, thank a lot for your help!

Answer 2

Functions and Methods are 2 different things. Read more about it here. Methods must be called with their parent class as the first argument:

class Fruit:
 def Taste(self):
 print "Yuck!"
# Call it
Fruit().Taste()

You could pass argv in this manner:

MyClass(*args, **kwargs).MyMethod(argv, **kwargs)

EDIT

Am I right in assuming that you'd like to pass 2 (or more) arguments to the command line so that they could be passed on to a function and executed? If yes, I'll try something simple here:

from sys import argv
try:
 a = argv[1]
 b = argv[2]
except IndexError:
 print "Enter both arguments"
class Integer:
 def Check(self, z):
 if int(z) < 0:
 print z, "is a negative integer"
 elif int(z) > 0:
 print z, "is a positive integer"
 else:
 print z, "is not an integer"
# Make instance
myclass = Integer()
# Call methods
myclass.Check(a)
myclass.Check(b)

• Kuba: My problem is I don't know how to call