task.md

Executing modules as scripts

A Python module is a file containing executable statements as well as function or class definitions. These statements are executed the first time the module name is encountered in an import statement. The file name is the module name with the suffix .py appended. Within a module, the module’s name (as a string) is available as the value of the global variable __name__.

When you run a module directly (that is, not by importing it into another one), the code in the module will be executed, just as if you imported it, but with __name__ set to "__main__".

You can use __name__ and __main__ like this:

if __name__ == "__main__":
   # Do something here

The statements inside this block will be executed only if the module is run directly and not through import into another module. For example, let's consider two files:

main_program:

import some_module

print(f"main_program __name__ is: {__name__}")

if __name__ == "__main__":
   print("main_program executed directly")
else:
   print("main_program executed when imported")

some_module:

print(f"some_module __name__ is: {__name__}")

if __name__ == "__main__":
   print("some_module executed directly")
else:
   print("some_module executed when imported")

Output after running main_program:

some_module __name__ is: some_module
some_module executed when imported
main_program __name__ is: __main__
main_program executed directly

Output after running some_module:

some_module __name__ is: __main__
some_module executed directly

For more structured and detailed information, you can refer to this Hyperskill knowledge base page.

Task

The files in this task are named the same as in the examples above, but their code is a bit different.

Modify task.py and some_module.py so that when you run task.py, your output is as follows:

This is a message from some_module.
This is a message from __main__.
This is a message from the function in the imported module.
This should be printed ONLY when task.py is called directly.