Circular import dependency in Python

Question

Let\'s say I have the following directory structure:

a\\
    __init__.py
    b\\
        __init__.py
        c\\
            __init__.py
            c_file.p         


        

Answer 1

Another solution is to use a proxy for the d_file.

For example, let's say that you want to share the blah class with the c_file. The d_file thus contains:

class blah:
    def __init__(self):
        print("blah")

Here is what you enter in c_file.py:

# do not import the d_file ! 
# instead, use a place holder for the proxy of d_file
# it will be set by a's __init__.py after imports are done
d_file = None 

def c_blah(): # a function that calls d_file's blah
    d_file.blah()

And in a's init.py:

from b.c import c_file
from b.d import d_file

class Proxy(object): # module proxy
    pass
d_file_proxy = Proxy()
# now you need to explicitly list the class(es) exposed by d_file
d_file_proxy.blah = d_file.blah 
# finally, share the proxy with c_file
c_file.d_file = d_file_proxy

# c_file is now able to call d_file.blah
c_file.c_blah()