Python circular importing?
So i'm getting this error
Traceback (most recent call last): File "/Users/alex/dev/runswift/utils/sim2014/simulator.py", line 3, in <module> from world import World File "/Users/alex/dev/runswift/utils/sim2014/world.py", line 2, in <module> from entities.field import Field File "/Users/alex/dev/runswift/utils/sim2014/entities/field.py", line 2, in <module> from entities.goal import Goal File "/Users/alex/dev/runswift/utils/sim2014/entities/goal.py", line 2, in <module> from entities.post import Post File "/Users/alex/dev/runswift/utils/sim2014/entities/post.py", line 4, in <module> from physics import PostBody File "/Users/alex/dev/runswift/utils/sim2014/physics.py", line 21, in <module> from entities.post import Post ImportError: cannot import name Post
and you can see that i use the same import statement further up and it works? Is there some unwritten rule about circular importing? How do i use the same class further down the call stack?
I think the currently accepted answer by jpmc26 comes down too heavily on circular imports. They can work just fine, if you set them up correctly.
The easiest way to do so is to use
import my_module syntax, rather than
from my_module import some_object. The former will almost always work, even if
my_module included imports us back. The latter only works if
my_object is already defined in
my_module, which in a circular import may not be the case.
To be specific to your case: Try changing
entities/post.py to do
import physics and then refer to
physics.PostBody rather than just
PostBody directly. Similarly, change
physics.py to do
import post and then use
post.Post rather than just