Multiple ,It Can't Be That Easy? Can It?,Nicknames

Multiple Files

By now, you have written some pretty big programs with lots of lines of code.
This can get pretty cumbersome to deal with. Lots of scrolling to find the right bit...
One of the ways to overcome this is to split the code into multiple files.
That's right. Your programs can consist of more than one python file. The main file will always run first, but you can put parts of your code into other files and bring them in to main.py by importing.
In fact, you've already done this whenever you've used import random, import time, import os and so on. It's just that on those occasions, you were importing code written by someone else.
Today, you'll create your own code file and import it into your main program.
👉 Let's start with a basic 'count to 10' program in the main.py file.
for i in range(10):
  print(i+1)

👉 Now let's move it to a new file.
In the files menu in your left hand toolbar, find the 'New file' icon and svelect it.

Name the file test.py - you MUST include the .py to specify that it's a python file.

 

Cut and paste the code from main.py to test.py.

 

By now, your main.py file should have nothing in it.
👉 Now click 'run'. Watch in amazement as nothing happens!
Remember, Python runs the code in the main.py file, which at the moment is empty. So we need to import the code.
👉 Go to your main.py file and add this code.
import test # No need for the .py

👉 Now run the code and watch the 'count to 10' program execute

 It Can't Be That Easy? Can It?

Well....... no. Because we can't control when the 'count to 10' program runs. It just runs on import. In this example, it would run before the print("Countdown") code. Not ideal.
import test
print("Countdown")

To solve this, we need to think more like libraries. They consist of a bunch of subroutines that we can import and then call only when we need them.
👉 Back in your test.py file, you need to make the countdown program a subroutine.

def countdown():
  for i in range(10):
    print(i+1)

👉 Finally, let's call it in our main.py file.
import test
print("Countdown")
test.countdown() # Test refers to the file, countdown to the subroutine in that file. 

Nicknames

If your file name is really long, you can give it a pseudonym, or nickname, as I believe the hip young things are calling them these days. This will save you time every time you want to run a subroutine from that file.
👉 Use as to nickname your file. Here I've used tt for the test file.
import test as tt
print("Countdown")
tt.countdown()