Unsual Import ..from.. behaviour

Python Help
1

So recently while working with imports, I came across a weird scenario.

Given a code file calc.py with the code below:

#calc.py

def add (x, y):
	return x + y

print ("peeping")

def subtract (x, y):
	return x - y

I decide to import just the add function from this module and print result of the function.

#use-calc.py

from calc import add

print (add(4, 5))

The output also returns the results of the global print function.

peeping
9

Is this accepted behavior or it is something we need to fix ? if it is correct then any documentation for the same. I dint want to post this on the bug tracker as am not sure its a valid bug or its my misunderstanding of the language.

1 Like
2

It is accepted and documented behavior. It is the reason for the

if __name__ == '__main__'

pattern.

3 Likes
3

This is expected. The first time a module is imported it is executed. The print function was part of the code executed when importing that module.

2 Likes
4

This can be surprising behavior when it is first encountered. Here is a useful discussion of what is going on when you import a module.