How to import library modules to my namespace from another module? - python

I have written this function inside my utils module
def megaimport(library_name):
skip_modules = ["sys", "os", "dir_path"]
exec(f"import {library_name}")
for module in dir(eval(library_name)):
if module.startswith("__") == False and module not in skip_modules:
exec(f"from {library_name}.{module} import *", globals(), locals())
What I am trying to achieve is to import all functions to my namespace from any library with the following structure:
library:
- module1.py
- function_1_1
- function_1_2
- module2.py
- function_2_1
- function_2_2
just by running in my notebook.ipynb:
from utils import megaimport
megaimport("library")
function_1_2()
function_2_1()
... etc
The idea is to dynamically call from library.module1 import *for every module in a library.
When I do this the function runs without errors but I when I call the functions they have not been imported properly. However, if I define the function in my code and run it it works as expected.
How can I import all the functions into my current namespace?
I am aware that importing everything like this is bad practice but for me it is convenient when working with jupyter notebooks.
My notebook.ipynb and utils.py live in the same directory.

Ok, after trying for a while I realised that I should pass globals() as a parameter to the function and pass it over to the exec in order to make it work in my namespace.
The function now looks like this:
import importlib
def megaimport(globals_dict, library_name):
skip_modules = ["sys", "os", "dir_path"]
mod = importlib.import_module(library)
for module in dir(mod):
if module.startswith("__") == False and module not in skip_modules:
exec(f"from {library_name}.{module} import *", globals_dict)
And it can be called just by:
from utils import megaimport
megaimport(globals(),"library")

Related

Why do *import ...* and *from x import y* idioms behave so differently here?

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)>

How do I import all functions from a package in python?

I have a directory as such:
python_scripts/
test.py
simupy/
__init__.py
info.py
blk.py
'blk.py' and 'info.py are modules that contains several functions, one of which is the function 'blk_func(para)'.
Within '__init__.py' I have included the following code:
import os
dir_path = os.path.dirname(os.path.realpath(__file__))
file_lst = os.listdir(dir_path)
filename_lst = list(filter(lambda x: x[-3:]=='.py', file_lst))
filename_lst = list(map(lambda x: x[:-3], filename_lst))
filename_lst.remove('__init__')
__all__ = filename_lst.copy()
I would like to access the function 'blk_func(para)', as well as all other functions inside the package, within 'test.py'. Thus I import the package by putting the following line of code in 'test.py':
from simupy import*
However, inorder to use the function, I still have to do the following:
value = blk.blk_func(val_param)
How do I import the package simupy, such that I can directly access the function in 'test.py' by just calling the function name? i.e.
value = blk_func(val_para)
Pretty easy
__init__.py:
from simupy.blk import *
from simupy.info import *
Btw, just my two cents but it looks like you want to import your package's functions in __init__.py but perform actions in __main__.py.
Like
__init__.py:
from simupy.blk import *
from simupy.info import *
__main__.py:
from simupy import *
# your code
dir_path = ....
It's the most pythonic way to do. After that you will be able to:
Run your script as a proper Python module: python -m simupy
Use your module as library: import simupy; print(simupy.bar())
Import only a specific package / function: from simupy.info import bar.
For me it's part of the beauty of Python..

How to import module without class in Python?

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

Import classes from child directory python

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

Python dynamic import and __all__

I am facing a behaviour that I don't understand even through I feel it is a very basic question...
Imagine you have a python package mypackage containing a module mymodule with 2 files __init__.py and my_object.py. Last file contains a class named MyObject.
I am trying to right an automatic import within the __init__.py that is an equivalent to :
__init__.py
__all__ = ['MyObject']
from my_object import MyObject
in order to be able to do:
from mypackge.mymodule import MyObject
I came up with a solution that fill all with all classes' names. It uses __import__ (also tried the importlib.import_module() method) but when I try to import MyObject from the mymodule, it keeps telling me:
ImportError: cannot import name MyObject
Here is the script I started with :
classes = []
for module in os.listdir(os.path.dirname(__file__)):
if module != '__init__.py' and module[-3:] == '.py':
module_name = module[:-3]
import_name = '%s.%s' % (__name__, module_name)
# Import module here! Looking for an equivalent to 'from module import MyObject'
# importlib.import_module(import_name) # Same behaviour
__import__(import_name, globals(), locals(), ['*'])
members = inspect.getmembers(sys.modules[import_name], lambda member: inspect.isclass(member) and member.__module__.startswith(__name__) )
names = [member[0] for member in members]
classes.extend(names)
__all__ = classes
Can someone help me on that point ?
Many thanks,
You just need to assign attributes on the module: globals().update(members).

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