9. Module

A module is a importable python file and can be created by creating a file with extension as .py

We can import the objects present in the module.

In the below 👇 example, we are importing hello function from greet module (greet.py)

greet.py

"""Module to greet the user"""

import getpass


def hello():
    """Greets the user."""
    username: str = getpass.getuser().capitalize()
    print(f"Hello {username}. Have a great day :)")


if __name__ == "__main__":
    hello()

from greet import hello

hello()

Hello Naveen. Have a great day :)

let’s have a look at the greet.py module. Well, we see the below if condition.

if __name__ == "__main__":
    hello()

But why do we we need to have it🤔? We can just call the hello function at the end as

hello()

Let’s see the below👇 code to know why we use the first approach rather than the second.🙃

import greet

🔍 The above code doesn’t greet you 😢

%run ./greet.py

Hello Naveen. Have a great day :)

But, this above code greets you😎.

The reason for this is, in the first snippet, we are importing a module called greet, so the actual code we are executing is in this REPL or Ipython shell.

Coming to second snippet, we are executing the greet.py directly.

Value of __name__ would be “__main__” if we are executing a Python module directly. If we import a module(using the module indirectly) then value of __name__ would be the relative path of the imported module. In the first example the __name__ in the greet module would be “greet”. As the “greet” is not equal to “__main__”, that’s the reason, we never went to the if condition when we imported greet module. 🙂