if __name__ == “__main__” in Python Explained Simply

If you just started learning Python, you’ve probably come across something like this:

# stuff
if __name__ == "__main__":
    # do stuff

This article will attempt to explain as simply as possible what is happening here, and the situations where if __name__ == "__main__" is required. Note that there are 2 underscore characters in front and behind name and main.

Long story short, this line of code allows us to ensure that we don’t accidentally run some code that we don’t intend to run. But let’s take a deeper dive into how this works exactly:

The Special __name__ Variable

The __name__ variable is set to a string variable "__main__" when we run our Python script normally. Let’s say we have 1 Python script first.py

first.py

print(__name__)

If we run first.py, like this:

python first.py  # for windows
pytohn3 first.py # for MacOS

We get this output:

__main__

Essentially, the __name__ variable in the Python script that we run first.py is set to the string value "__main__". However, this behaviour differs when there are multiple Python…