Attempted relative import with no known parent package
Python 3.xPython ImportImporterrorPython 3.x Problem Overview
from ..box_utils import decode, nms
This line is giving error
> ImportError: attempted relative import with no known parent package
What is this error and how to resolve this error?
Python 3.x Solutions
Solution 1 - Python 3.x
Apparently, box_utils.py isn't part of a package. You still can import functions defined in this file, but only if the python script that tries to import these functions lives in the same directory as box_utils.py, see this answer.
Nota bene: In my case, I stumbled upon this error with an import statement with one period, like this:
from .foo import foo. This syntax, however, tells Python that foo.py is part of a package, which wasn't the case. The error disappeared when I removed the period.
Solution 2 - Python 3.x
If a different dictionary contains script.py, it can be accessed from the root. For instance:
If your program is structured...:
/alpha
/beta
/delta
/gamma
/epsilon
script.py
/zeta
...then a script in the epsilon directory can be called by:
from alpha.gamma.epsilon import script
Solution 3 - Python 3.x
package
|--__init__.py
|--foo.py
|--bar.py
Content of bar.py
from .foo import func
...
If someone is getting the exactly same error for from .foo import func.
It's because you've forgot to make it a package. So you just need to create __init__.py inside package directory.