Did you know about this in Python?

Key Takeaways

I have this calculator.py file. Now this is a file that I might directly run myself. And if I want to do that, I can press run and you can see that it says this is a simple calculator. I can enter some numbers and then I get the sum and the difference of those values. This is great and it contains some functions. Now these functions are things that are reusable, right? And we may actually want to reuse them in some other Python code. So for example, I may have another Python program. Let's call it program.py. And we may want to reuse some of the logic in our calculator program. But watch what happens when I run this Python code. Going to go ahead and run it. And you'll see that it starts by saying this is a simple calculator. Now that's not what that said in this script. This script says using the calculator module. What happened here is we started by running all of the code that was inside of this calculator module and then we ran all of the code that was inside of this program module. So this is exactly where the if_ame underscore is equal to underscore main comes in. This is a convention that allows you to control when code is executed. So I'm going to add it here and you're going to immediately see how it works. Okay, so you can see that I have if name is equal to main with the double underscores. What's going to happen is this code will now only execute if this module is ran directly, not if it is imported. So let me show you what I mean. Now if I go and I run my calculator.py pi file. You can see that this works and it runs. But if I run my program.py file, it no longer runs this code.