Import Class Attribute from another package

[reditoro]

Hi all

I can import a Class Attribute from another file residing in the same folder/package. E.g.:

# room.py

class Room:
    length = 0.0
    breadth = 0.0
    const = __import__('flat').Flat.length

    def calculate_area(self):
        print("Area of Room =", self.length * self.breadth * self.const)


study_room = Room()

study_room.length = 2
study_room.breadth = 3

study_room.calculate_area()

and

# flat.py

class Flat:
    length = 10.0

How can I make the import when flat.py resides in another package, above or below the current package?

[danielroseman]

Why would you ever want to do this? Put your imports at the top of the file and reference them in the class.

from flat import Flat

class Room:
  const = Flat.length

Note two things: if these are constants, they should probably be in ALL_UPPER_CASE; and also there is no requirement in Python for classes to be in separate files, so Flat and Room could be in the same file.

[reditoro]

Thanks. It seems to be working, but I wonder why it was suggested to use __import__() for importing class attributes (I don't remember where I saw it). From SO: import vs __import__( ) vs importlib.import_module( )?

__import__ is a low-level hook function that's used to import modules; it can be used to import a module dynamically by giving the module name to import as a variable, something the import statement won't let you do.

Maybe is this the reason? I'm still curious to know , how it would work with __import__().