programing tip

문자열 변수에서 모듈 가져 오기

itbloger 2020. 5. 31. 20:54
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문자열 변수에서 모듈 가져 오기


관심있는 서브 모듈 패키지가 제공하는 MPL 자체 라이브러리와는 다른 MPL (nested matplotlib) 라이브러리에 대한 문서 (개인용)를 작성하고 있습니다. 향후 MPL 릴리스에서 문서 생성을 자동화 할 Python 스크립트를 작성 중입니다.
관심있는 서브 모듈 / 패키지를 선택하고 목록을 생성하고 처리 할 기본 클래스를 나열하려고합니다.pydoc

문제는 파이썬이 문자열에서 하위 모듈을로드하도록 지시하는 방법을 찾을 수 없다는 것입니다. 내가 시도한 것의 예는 다음과 같습니다.

import matplotlib.text as text
x = dir(text)

.

i = __import__('matplotlib.text')
y = dir(i)

.

j = __import__('matplotlib')
z = dir(j)

다음은 pprint를 통해 위 목록을 3 가지 방법으로 비교 한 것입니다.

여기에 이미지 설명을 입력하십시오

I don't understand what's loaded in y object - it's base matplotlib plus something else, but it lack information that I wanted and that is main classes from matplotlib.text package. It's top blue coloured part on screenshot (x list)

Please don't suggest Sphinx as different approach.


The __import__ function can be a bit hard to understand.

If you change

i = __import__('matplotlib.text')

to

i = __import__('matplotlib.text', fromlist=[''])

then i will refer to matplotlib.text.

In Python 2.7 and Python 3.1 or later, you can use importlib:

import importlib

i = importlib.import_module("matplotlib.text")

Some notes

  • If you're trying to import something from a sub-folder e.g. ./feature/email.py, the code will look like importlib.import_module("feature.email")

  • You can't import anything if there is no __init__.py in the folder with file you are trying to import


importlib.import_module is what you are looking for. It returns the imported module. (Only available for Python >= 2.7 or 3.x):

import importlib

mymodule = importlib.import_module('matplotlib.text')

You can thereafter access anything in the module as mymodule.myclass, etc.


spent some time trying to import modules from a list, and this is the thread that got me most of the way there - but I didnt grasp the use of ___import____ -

so here's how to import a module from a string, and get the same behavior as just import. And try/except the error case, too. :)

  pipmodules = ['pycurl', 'ansible', 'bad_module_no_beer']
  for module in pipmodules:
      try:
          # because we want to import using a variable, do it this way
          module_obj = __import__(module)
          # create a global object containging our module
          globals()[module] = module_obj
      except ImportError:
          sys.stderr.write("ERROR: missing python module: " + module + "\n")
          sys.exit(1)

and yes, for python 2.7> you have other options - but for 2.6<, this works.


I developed these 3 useful functions:

def loadModule(moduleName):
    module = None
    try:
        import sys
        del sys.modules[moduleName]
    except BaseException as err:
        pass
    try:
        import importlib
        module = importlib.import_module(moduleName)
    except BaseException as err:
        serr = str(err)
        print("Error to load the module '" + moduleName + "': " + serr)
    return module

def reloadModule(moduleName):
    module = loadModule(moduleName)
    moduleName, modulePath = str(module).replace("' from '", "||").replace("<module '", '').replace("'>", '').split("||")
    if (modulePath.endswith(".pyc")):
        import os
        os.remove(modulePath)
        module = loadModule(moduleName)
    return module

def getInstance(moduleName, param1, param2, param3):
    module = reloadModule(moduleName)
    instance = eval("module." + moduleName + "(param1, param2, param3)")
    return instance

And everytime I want to reload a new instance I just have to call getInstance() like this:

myInstance = getInstance("MyModule", myParam1, myParam2, myParam3)

Finally I can call all the functions inside the new Instance:

myInstance.aFunction()

The only specificity here is to customize the params list (param1, param2, param3) of your instance.

참고 URL : https://stackoverflow.com/questions/8718885/import-module-from-string-variable

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