I have 4 files in my project:
project/__init__.py
project/app.py
project/mod_x.py
project/mod_y.py
In mod_x.py I have a class (e.g. ModX)
In mod_y.py I have just one function.
I import modules from app.py as follows:
from .mod_x import ModX
import .mod_y
I get an error:
ImportError: No module named 'mod_y'
Before I created init.py I didn't have that kind of problems (of course, I dont put "." before module name).
How to import module which doesn't have the class inside in Python3 with init.py file inside the current directory?
Relative imports are only available for from...import syntax.
You could import that function this way:
from .mod_y import FUNCTION_NAME
Module could be imported this way:
from . import mod_y
Related
below the folder structure of my software:
below the code of all the .py files:
run.py:
import modules.module_01.aa as a
a.test()
# test:
if __name__=="__main__":
pass
aa.py (module 1):
import libraries.qq as q
import libraries.zz as z
def test():
q.qq_fun()
z.zz_fun()
print("ciao")
qq.py (library used by aa.py):
def qq_fun():
pass
zz.py (library used by aa.py):
def zz_fun():
pass
my question is really simple, why when I run "run.py" Python say to me:
why "aa.py" can't import the module "qq.py" and "zz.py"? how can I fix this issue?
run.py
In run.py, the Python interpreter thinks you're trying to import module_01.aa from a module named module. To import aa.py, you'll need to add this code to the top of your file, which adds the directory aa.py is in to the system path, and change your import statement to import aa as a.
import sys
sys.path.insert(0, "./modules/module_01/")
aa.py
The same problem occurs in aa.py. To fix the problem in this file, you'll need to add this code to the top of aa.py, which adds the directory qq.py and zz.py are in, and remove the libraries. from both of your import statements.
import sys
sys.path.insert(0, "./modules/module_01/libraries")
e.g.
import os as my_os
import my_os.path
ModuleNotFoundError: No module named 'my_os'
but the following script is ok
import os
import os.path
You can't do that in Python.
import statements are importing from Python file names.
You aren't renaming the file of os to my_os, therefore this wouldn't work.
As mentioned in the documentation:
The import statement combines two operations; it searches for the named module, then it binds the results of that search to a name in the local scope.
Tried the similar way as os.py did:
import json as my_json
from my_json.decoder import * # ModuleNotFoundError: No module named 'my_json'
import sys
import json.decoder as my_decoder
sys.modules['my_json.decoder'] = my_decoder
from my_json.decoder import * # it's ok now
I have a package structure like this:
- src
- src/main.py
- src/package1
- src/package1/__init__.py
- src/package1/module1.py
- src/package1/module2.py
... where module2 is a subclass of module1, and therefore module1 gets referenced by an absolute import path in module2.py.
That is, in src/package1/module2.py:
from package1.module1 import SomeClassFromModule1
The problem occurs in the main.py script:
## here the imports
def main():
# create an instance of the child class in Module2
if __name__ == "__main__":
main()
Option 1 works. That is, in src/main.py:
from package1.module2 import SomeClassFromModule2
some_name = SomeClassFromModule2()
Option 2 does not work. That is, in src/main.py:
import package1.module2.SomeClassFromModule2
some_name = package1.module2.SomeClassFromModule2()
... causes the following error.
ModuleNotFoundError: No module named 'package1.module2.SomeClassFromModule2'; 'package1.module2' is not a package
So why is there this difference between the import and from ... import idiom?
Would be glad for some clarification.
import x keyword brings all the methods and class from x in the the file it is being called.
from x import y this brings a specific method or class('y' is a method or class) from that .py file ('x' is the file here) instead of bringing all the methods it has.
In your case when you import package1.module2 the SomeClassForModule2() is being already imported and hence you need not write import package1.module2.SomeClassFromModule2
here I guess you want to access a class, so you need to create a object in order to access it.
hope this helped you
After some test, I think you cannot import a function or class by using import your_module.your_class.
It's all about package, module, function and class:
# import module
>>>import os
<module 'os' from ooxx>
#use module of module (a litte weird)
>>>os.path
<module 'posixpath' from ooxx>
#import module of module (a litte weird)
>>>import os.path
#use function
>>>os.path.dirname
<function posixpath.dirname(p)>
# you cannot import a function (or class) by using 'import your.module.func'
# 'import ooxx' always get a module or package.
>>>import os.path.dirname
ModuleNotFoundError
No module named 'os.path.dirname'; 'os.path' is not a package
# instead of it, using 'from your_module import your_function_or_class'
>>>from os.path import dirname
<function posixpath.dirname(p)>
I've been trying to import some python classes which are defined in a child directory. The directory structure is as follows:
workspace/
__init__.py
main.py
checker/
__init__.py
baseChecker.py
gChecker.py
The baseChecker.py looks similar to:
import urllib
class BaseChecker(object):
# SOME METHODS HERE
The gChecker.py file:
import baseChecker # should import baseChecker.py
class GChecker(BaseChecker): # gives a TypeError: Error when calling the metaclass bases
# SOME METHODS WHICH USE URLLIB
And finally the main.py file:
import ?????
gChecker = GChecker()
gChecker.someStuff() # which uses urllib
My intention is to be able to run main.py file and call instantiate the classes under the checker/ directory. But I would like to avoid importing urllib from each file (if it is possible).
Note that both the __init__.py are empty files.
I have already tried calling from checker.gChecker import GChecker in main.py but a ImportError: No module named checker.gChecker shows.
In the posted code, in gChecker.py, you need to do
from baseChecker import BaseChecker
instead of import baseChecker
Otherwise you get
NameError: name 'BaseChecker' is not defined
Also with the mentioned folders structure you don't need checker module to be in the PYTHONPATH in order to be visible by main.py
Then in main.y you can do:
from checker import gChecker.GChecker
I'm having an issue with the import statement in Python 3. I'm following a book (Python 3 Object Oriented) and am having the following structure:
parent_directory/
main.py
ecommerce/
__init__.py
database.py
products.py
payments/
__init__.py
paypal.py
authorizenet.py
In paypal.py, I'm trying to use the Database class from database.py. So I tried this:
from ecommerce.database import Database
I get this error:
ImportError: No module named 'ecommerce'
so I try with both of these import statements:
from .ecommerce.database import Database
from ..ecommerce.database import Database
and I get this error:
SystemError: Parent module '' not loaded, cannot perform relative import
What am I doing wrong or missing?
Thank you for your time!
Add your parent_directoryto Python's search path. For example so:
import sys
sys.path.append('/full/path/to/parent_directory')
Alternatively, you can add parent_directory to the environmental variable PYTHONPATH.