I'm working on a documentation (personal) for nested matplotlib (MPL) library, which differs from MPL own provided, by interested submodule packages. I'm writing Python script which I hope will automate document generation from future MPL releases.
I selected interested submodules/packages and want to list their main classes from which I'll generate list and process it with pydoc
Problem is that I can't find a way to instruct Python to load submodule from string. Here is example of what I tried:
import matplotlib.text as text
x = dir(text)
.
i = __import__('matplotlib.text')
y = dir(i)
.
j = __import__('matplotlib')
z = dir(j)
And here is 3 way comparison of above lists through pprint:
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.
This question is related to
python
matplotlib
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.
Apart from using the importlib
one can also use exec
method to import a module from a string variable.
Here I am showing an example of importing the combinations
method from itertools
package using the exec
method:
MODULES = [
['itertools','combinations'],
]
for ITEM in MODULES:
import_str = "from {0} import {1}".format(ITEM[0],', '.join(str(i) for i in ITEM[1:]))
exec(import_str)
ar = list(combinations([1, 2, 3, 4], 2))
for elements in ar:
print(elements)
Output:
(1, 2)
(1, 3)
(1, 4)
(2, 3)
(2, 4)
(3, 4)
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.
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.
Source: Stackoverflow.com