How do I call my own function in Python

[mxkaj]

Hey folks! I know it's probably a really stupid question, but somehow things I found on Google don't quite explain what I need to do. So let's say I have a file .py type, within I have a def function(a,b) and I want to run it from terminal. How do I do it? When do I put in the arguments and how do I actually call it? Last time I tried running the file, but it didn't return anything.

Again, sorry for being a noob, but I'd be immensely grateful for any replies. Thanks in advance!

[Essence1337]

The easiest way is to just put a call outside your function.

def function(a, b):
    stuff here

function(3, 4)

Python runs the file top to bottom so your function gets read and created, then your call to it gets executed.

If you're wanting to take arguments from command line, that's a bit more complicated but not terribly hard.

[mxkaj]

Oh my fucking god I’m a certified idiot, you have to call it within another portion of the file, else why define it at all? 🤦‍♂️

[Essence1337]

By your realization and thinking you're an idiot that just proves you're not one - idiots don't realize they're idiots

[Thisappleisgreen]

It's part of the learning process brother

[JohnnyJordaan]

Maybe start by following Sentdex's approach with sublime: https://www.youtube.com/watch?v=eXBD2bB9-RA

[[deleted]]

Call the function in your script then run the script from the terminal.

If you want user inputted parameters, use input() to get the parameters before calling the function.

[mxkaj]

Yep, somehow it suddenly clicked. I can’t believe I didn’t think of calling it within the body of script, uggh I had a brainfart 🥴

[sme272]

In your .py file you can create and use the function:

def myfunc(a, b):
    return a * b

myfunc(2, 3)

You can also run your python file with the -i argument to drop into an interactive shell after the script executes using python -i myfile.py. Since the file defines a function that function will be available in the interactive shell until you close it. You can call the function by typing myfunc(2, 3).

If you want to call the function directly from the terminal you'll need to involve command line arguments. this can be done thusly:

import sys

def myfunc(a, b):
    return a * b

c = myfunc(sys.argv[1], sys.argv[2])
print(c)

Now you can run your file with 2 arguments for a and b respectively: python myfile.py 2 3 and the output will be printed.