In programming terms, what do you call this import behavior?

Question

I have a file called "const_a.py" it has this in it

ONE = 1
TWO = 2

Then I have another const file called "const_b.py" it has this

from const_a import *

THREE = 3
FOUR = 4

Finally I am printing out some values in test.py

from const_b import *

print(ONE)
print(THREE)

That prints out 1 and 3. I would have expected it to error out trying to print ONE. Apparently const_b now has const_a in it.

What is this behavior called? Is it intentional?

It's called *importing*. In `const_by.py` you did `from const_a import *` which assigns everything in `const_a` to the same name in `const_b`'s global namespace — juanpa.arrivillaga, Feb 07 '18 at 18:32
You've imported all names from `const_a` into `const_b` and then all names from `const_b` into `__main__`, so there's no reason why it shouldn't work. — Ignacio Vazquez-Abrams, Feb 07 '18 at 18:32

chepner · Accepted Answer · 2018-02-07T18:36:14.630

4

from const_a import * is effectively equivalent to

import const_a
ONE = const_a.ONE
TWO = const_a.TWO
del const_a

You are creating names in const_b whose values are taken from the identically named variables in const_a.

edited Feb 07 '18 at 18:36

answered Feb 07 '18 at 18:34

chepner

1 Answers1