name Variable
2 min read ·
What is name?
__name__ is a special built in variable in Python.It tells how a Python file is being used:
- Whether it is run directly
- Or imported as a module
main Concept
When a Python file is executed directly, Python automatically sets:
When the same file is imported into another file, the value of
__name__ becomes the module name.Example
File:
example.pyCase 1: Run directly
Output:
Case 2: Import in another file
Output:
Note
This behavior helps Python identify whether the file is the main program or just a module.
Why name is Used
It is used to control which part of code should run.
Without it, all code in a file runs even when imported.
Proper Usage
What Happens Here
- If file runs directly →
main()executes - If imported →
main()does not execute
Pro Tip
Always wrap execution code inside a main function and use name check for better structure.
Real-world Usage
In real applications:
- You write reusable functions in modules
- You write test or execution code inside
if __name__ == "__main__"
Example:
- When imported → only functions are available
- When run → test code executes
Real World Scenario
Developers use name to separate reusable logic from execution logic, especially in large projects and libraries.
Exercise
Create a file demo.py:
- Define two functions
- Add print statements inside main block
Import it into another file and observe which code runs.